Method for making light-blocking articles

ABSTRACT

A foamed, opacifying element useful as a light-blocking article is prepared with a dry opacifying layer on a substrate. The dry opacifying layer is densified, followed by application of a functional composition formulation to form a functional composition upon drying and curing at a coverage of 0.5-15 g/m 2 . The functional composition comprises at least: (i) glass particles such as hollow glass particles at a coverage of 0.1-2.2 g/cm 2 , and can also include any or combination of a (iv) water-soluble or water-dispersible organic polymeric binder that may be crosslinked, thickeners, coating aids having an HLB of at least 5, (ii) lubricants, (iii) tinting materials, and (v) crosslinking agents. Among other properties, the presence of the glass particles provides additional heat absorption for the foamed, opacifying elements that can be formed into light-blocking materials.

RELATED APPLICATIONS

This application is a continuation-in-part of prior U.S. patentapplication Ser. No. 16/203,737, filed Nov. 29, 2018, which is herebyincorporated herein by reference in its entirety.

Reference is also made to the following copending and commonly assignedpatent applications:

U.S. Ser. No. 16/______ (filed on even date herewith by Nair andSwanton), and entitled “Aqueous Functional Composition for Articles”(Attorney Docket K002270US03/JLT);

U.S. Ser. No. 16/018,332 (filed Jun. 26, 2018 by Nair, Lobo, andDonovan), published as U.S. Patent Application Publication 2019/0390027;

U.S. Ser. No. 16/018,350 (filed Jun. 26, 2018 by Lobo, Nair, andDonovan), published as U.S. Patent Application Publication 2019/0390028;and

U.S. Ser. No. 16/018,367 (filed Jun. 26, 2018 by Nair, Lobo, andDonovan), published as U.S. Patent Application Publication 2019/0390029;

the disclosures of all of which are incorporated herein by reference.

FIELD OF THE INVENTION

In general, this invention relates to a method for making light-blockingarticles such as shades, curtains, and other coated articles that blockambient light. More specifically, this invention relates to a method formaking foamed, opacifying elements having a functional compositiondisposed on a dry opacifying layer. The functional composition can servea variety of functions because of the incorporation therein of variousmaterials including hollow glass particles.

BACKGROUND OF THE INVENTION

In general, when light strikes a surface, some of it may be reflected,some absorbed, some scattered, and the rest transmitted. Reflection canbe diffuse, such as light reflecting off a rough surface such as a whitewall, in all directions, or specular, as in light reflecting off amirror at a definite angle. An opaque substance transmits almost nolight, and therefore reflects, scatters, or absorbs all of it. Bothmirrors and carbon black are opaque. Opacity depends on the frequency ofthe light being considered. “Blackout” or light blocking materialstypically refer to coated layers in articles that are substantiallyimpermeable to light such as visible or UV radiation. Thus, when ablackout material such as a blackout curtain or shade is hung over awindow, it generally blocks substantially all external light fromentering the room through that window. Blackout materials are suitableas curtains and shades for domestic use, for institutional use inhospitals and nursing homes, as well as for use in commercialestablishments such as hotels, movie theaters, and aircraft windowswhere the option of excluding light can be desirable.

Light blocking articles such as the blackout curtains or shades can becomprised of a fabric (porous) substrate coated with more than one layerof a foamed latex composition. There is a desire for these curtains, inaddition to blocking transmitted light, to have a light color (hue)facing the environment where an activity needs illumination in order tominimize the amount of artificial lighting needed to perform theactivity. An example is when the function of the blackout material is toseparate two areas of activity where one or both areas can beartificially lit at the same time. More often than not, the function ofa blackout curtain is to prevent sunlight from entering a room through abuilding window. It can also be desirable for the color (hue) of theside facing the window to match the external décor of the building.

Porous fabrics are derived from yarns of manmade or naturally-occurringthreads that are woven or knitted together. Threads used to make yarnare often twisted together to form the threads. Synthetic plasticcoating materials, such as polyvinyl chloride, led to the emergence offabrics woven from plastic coated yarns. Such fabrics have increaseddurability and wear properties compared to fabrics made fromnaturally-occurring fibers. One use for such fabrics is window shadesespecially for commercial and hospital sites.

Light colored blackout curtains theoretically can be made by coatingporous fabrics with light colored foams containing light scatteringpigments such as titanium dioxide or clays. However, very thick foamcoatings will be needed to create blackout curtains through which thesun is not visible in a darkened room using only these pigments. Amethod that is practiced for reducing the weight of such blackoutmaterials is to sandwich a light-absorbing, foamed black or greypigment, such as a carbon black layer between two foamed lightscattering, white pigment-containing layers.

When an electromagnetic radiation blocking coating has, as it oftendoes, a strongly light absorbing material containing black pigments suchas carbon black, between two reflective layers, it has at least twodistinct problems. First, such coatings require three or more separatecoating operations that reduce manufacturing productivity and increaseunit costs. Secondly, carbon black in the light absorbing middle layercan become “fugitive” (or non-enclosed) from some puncture or tearoccurring during sewing or laundering, and soil other layers such as thereflective layers, which is highly objectionable. Additionally, thestitches generated in the materials during sewing can cause the fugitivecarbon from the light absorbing layer to spread over a larger areathereby increasing the area of objectionable shading of thelight-colored surface.

U.S. Pat. No. 7,754,409 (Nair et al.), U.S. Pat. No. 7,887,984 (Nair etal.), U.S. Pat. No. 8,252,414 (Putnam et al.), and U.S. Pat. No.8,329,783 (Nair et al.) describe porous polymer particles that are madeby a multiple emulsion process, wherein the multiple emulsion processprovides formation of individual porous particles comprising acontinuous polymer phase and multiple discrete internal pores, and suchindividual porous particles are dispersed in an external aqueous phase.The described Evaporative Limited Coalescence (ELC) process is used tocontrol the particle size and distribution while a hydrocolloid isincorporated to stabilize the inner emulsion of the multiple emulsionthat provides the template for generating the pores in the porousparticles.

U.S. Pat. No. 9,891,350 (Lofftus et al.) describes improved articlesthat are designed with an opacifying layer that is capable of blockingpredetermined electromagnetic radiation. The opacifying layer isdisposed on a substrate that can be composed of any suitable materialand an underlying layer can be incorporated between the substrate andthe opacifying layer. While these articles have numerous advantages, andrepresent an important advance in the art, there is a need for furtherimprovement in providing opacifying articles that are lighter in weight;and that have improved flexibility, good “hand,” while maintaining lightcoloration of the surfaces facing an observer without losingreflectivity, and light-absorptive properties; launderability; andminimizing dark opacifying agents getting out into the environment uponstitching and handling.

An improvement in this art is provided by the foamed aqueouscompositions described in U.S. Pat. No. 9,469,738 (Nair et al.) in whichvery small amounts of opacifying colorants incorporated into porousparticles can be incorporated into a latex foam, and the resultingcomposition has a foam density of at least 0.1 g/cm³.

U.S. Pat. No. 9,963,569 (Nair et al) describes a method for providing afoamed, opacifying element includes providing a foamable aqueous latexcomposition comprising porous particles incorporating within them verysmall amounts of opacifying colorants, aerating it to a specific foamdensity, applying the foamed aqueous latex composition to a poroussubstrate, drying, and densifying the dried layer.

U.S. Pat. No. 4,677,016 (Ferziger) describes a foam-coated, tightlywoven fiberglass fabric where at least one surface thereof is coatedwith one or more layers of a flame retardant foamed latex coatingcomposition. At least one of the foam coating layers is opaque andcomprises a cured layer of flame retardant polymeric latex foam.

Copending U.S. Ser. Nos. 16/018,332, 16/018,350, and 16/018,367described above describe opacifying elements having improved propertiesdue to the presence of a functional composition disposed on a dryopacifying layer.

The opacifying layers described in these copending applications have afunctional layer disposed over an opacifying layer that is coated on oneside of a fabric. The primary purposes of the functional layer are toprevent “blocking”: i) when a fabric with an opacifying layer is inprolonged physical contact with another opacifying layer deposited onanother fabric with each other and to prevent sticking of these layerswhen they are separated; and ii) when the article of the fabric with theopacifying layer is subjected to the conditions of a thermal dyetransfer process and the opacifying layer is under contact with asurface under high temperature and pressure during the transfer processto enable easy separation from the surface.

The properties of the functional layer when a thermal dye transferprocess is used are more demanding than those needed for theanti-blocking function. During a thermal dye transfer process, a fabricis kept in contact with the donor element containing a patterncomprising thermal dyes. The opacifying layer with its superimposedfunctional layer is kept, either, directly in contact with a blanketbelt or separated from the belt by an intervening “ghosting” paper thatis fabricated with release agents. The entire package can be subjectedto a nip at a pressure of about 2-3 psi (0.14-0.21 kgf/cm²) and 400° F.(204° C.) temperature for up to 35 seconds, during which the thermaldye(s) sublime from a dye donor(s) into the fabric. At the end of thiscontact period, both sides of the fabric are expected to release easilyand cleanly from the donor element and the blanket belt.

Because the opacifying layer comprises a crosslinked latex binder whoseglass transition temperature (T_(g)) is lower than the temperatureacquired by the opacifying layer during the thermal dye transferprocess, the propensity to stick to the substrate in contact, is high.This necessitates the presence of a functional layer over the opacifyinglayer. While the spacer particles used in the functional layer describedin the noted copending patent applications meet the requirements forthermal dye transfer printing, a problem can arise if the spacerparticles change the appearance of the article. Polymeric spacerparticles are generally opaque and can scatter light and therefore theycan make the opacifying layer and functional layer appear lighter incolor. While a lighter-colored coating is of itself not a significantproblem, any non-uniformity in the functional layer may be more visuallynoticeable in terms of haze or whiteness in spots, streaks, or patches.Another potential problem with polymer spacer beads known in the art isthe challenge to make materials whose glass transition temperature ishigher than the operational temperature of 225° C. of a thermal dyetransfer printer.

Thus, there is a continued need for improvements in known light-blockingarticles that overcome such problems and that improve reflection ofthermal energy.

SUMMARY OF THE INVENTION

The present invention provides a method for preparing a foamed,opacifying element, the method comprising the steps of:

A) providing a substrate having a first opposing side and a secondopposing side,

B) applying a foamed aqueous composition onto the first opposing side ofthe substrate,

C) drying the applied foamed aqueous composition, to provide a dryopacifying layer;

D) densifying the dry opacifying layer to reduce its thickness by atleast 20% compared to its original thickness;

E) applying a functional composition formulation comprising (i) glassparticles, to the dry opacifying layer, and

F) curing the applied functional composition formulation and the dryopacifying layer to provide a functional composition on the dryopacifying layer,

-   -   thereby providing a foamed, opacifying element,    -   wherein:    -   the dry opacifying layer comprises:    -   (a) at least 0.1 weight % and up to and including 35 weight % of        porous particles, each porous particle comprising a continuous        polymeric phase and discrete pores dispersed within the        continuous polymeric phase, the porous particles having a mode        particle size of at least 2 μm and up to and including 50 μm;    -   (b′) at least 10 weight % and up to and including 80 weight % of        a matrix material that is derived from a (b) binder material        having a glass transition temperature (T_(g)) of less than 25°        C.;    -   (c) at least 0.0001 weight % and up to and including 50 weight %        of one or more additives selected from the group consisting of        dispersants, foaming agents, foam stabilizing agents,        plasticizers, flame retardants, optical brighteners, thickeners,        biocides, tinting colorants, metal particles, and inert        inorganic or organic fillers;    -   (d) less than 5 weight % of water; and    -   (e) at least 0.002 weight % of an opacifying colorant different        from all of the one or more additives of (c), which opacifying        colorant absorbs electromagnetic radiation having a wavelength        of at least 380 nm and up to and including 800 nm,    -   all amounts being based on the total weight of the dry        opacifying layer.

The present invention utilizes foamable and foamed aqueous compositionsto provide foamed, opacifying elements such as window shades, curtains,and other light-blocking materials that contain low amounts ofopacifying colorants in a light-blocking, dry opacifying layer. Thefoamed, opacifying elements prepared according to the present inventionalso have a functional composition disposed over (in some embodiments,directly on) the light-blocking, dry opacifying layer to provide uniquesurface properties.

It was discovered that the use of glass particles or spheres (such ashollow glass particles) in the functional composition can overcomeproblems. For example, the glass particles are generally transparent inthe visible spectrum of light. The preferred hollow glass particles arelight in weight and are also capable of reflecting and scatteringradiation, preferentially over solid glass particles. The ability toreflect and scatter incident radiation in the functional composition ofthe foamed, opacifying elements allows resulting fabric articles toabsorb less heat relative to fabric articles that do not contain anyglass particles in the noted location.

The functional composition used in the present invention can alsomitigate the problem of sticking due to the presence of microscopicprotrusions or asperities from the glass particles that help minimizesurface contact between the dry opacifying layer and any other solidsurface.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion is directed to various embodiments of thepresent invention and while some embodiments can be desirable forspecific uses, the disclosed embodiments should not be interpreted orotherwise considered to limit the scope of the present invention, asclaimed below. In addition, one skilled in the art will understand thatthe following disclosure has broader application than is explicitlydescribed for any specific embodiment.

Definitions

As used herein to define various components of the foamed aqueouscomposition, foamable aqueous composition, functional compositionformulations, or materials used to prepare the porous particles, unlessotherwise indicated, the singular forms “a,” “an,” and “the” areintended to include one or more of the components (that is, includingplurality referents).

Each term that is not explicitly defined in the present application isto be understood to have a meaning that is commonly accepted by thoseskilled in the art. If the construction of a term would render itmeaningless or essentially meaningless in its context, the termdefinition should be taken from a standard dictionary.

The use of numerical values in the various ranges specified herein,unless otherwise expressly indicated otherwise, are considered asapproximations as though the minimum and maximum values within thestated ranges were both preceded by the word “about.” In this manner,slight variations above and below the stated ranges can be used toachieve substantially the same results as the values within the ranges.In addition, the disclosure of these ranges is intended as a continuousrange including every value between the minimum and maximum values.

Unless otherwise indicated, the terms “foamed, opacifying element,”“light-blocking element,” and “element” are intended to be synonymousterms referring to the same article.

Unless otherwise indicated, the terms “foamed aqueous composition” and“foamed composition” are intended to be synonymous terms and to refer tothe same material, and are different from a “functional composition” and“functional composition formulation” as described below.

The terms (a) “porous particle” and (a) “porous particles” are usedherein, unless otherwise indicated, to refer to porous organic polymericmaterials useful in the foamable aqueous compositions, foamed aqueouscompositions, and foamed, opacifying elements according to the presentinvention. The (a) porous particles generally comprise a solidcontinuous polymeric phase having an external particle surface anddiscrete pores dispersed within the continuous polymeric phase. Thecontinuous polymeric phase also can be chemically crosslinked orelastomeric in nature, or both chemically crosslinked and elastomeric innature.

The continuous polymeric phase of the (a) porous particles generally hasthe same composition throughout that solid phase. That is, thecontinuous polymeric phase is generally uniform in composition includingany materials [for example, (e) opacifying colorant] that can beincorporated therein. In addition, if mixtures of organic polymers areused in the continuous polymeric phase, generally those mixtures alsoare dispersed uniformly throughout.

As used in this disclosure, the term “isolated from each other” refersto the different (discrete) pores of same or different sizes that areseparated from each other by some material of the continuous polymericphase, and such pores are not interconnected. Thus, “discrete” poresrefer to “individual” or “closed,” non-connected pores or voidsdistributed within the continuous polymeric phase.

When used herein, the terms “first discrete pore” and “second discretepore” refer to distinct sets of individual pores in the (a) porousparticles. Each distinct set of pores includes a plurality of discretepores, each of which discrete pores is isolated from others discretepores in the distinct set of pores, and the discrete pores of eachdistinct set of pores are isolated from all other discrete pores of theother distinct sets of pores in the (a) porous particles. Each distinctset of pores can have the same mode average size or both sets can havethe same mode average size. For making such (a) porous particles, theword “discrete” can also be used to define different droplets of thefirst and second aqueous phases when they are suspended in the oil(solvent) phase (described below).

Where there are different sets of discrete pores, the discrete pores ofa first set can be predominantly nearer then external particle surfacecompared to the discrete pores of a second set. For example, a set ofsmaller discrete pores can be predominantly close to the externalparticle surface compared to a set of larger discrete pores. As usedherein, the term “predominant” means that a larger number fraction ofdiscrete pores of one size is found in a “shell” area nearer the surfaceof the (a) porous particle than one would expect based on the totalnumber fraction of the two or more types (sizes) of discrete porespresent in the (a) porous particle.

The (a) porous particles can include “micro,” “meso,” and “macro”discrete pores, which according to the International Union of Pure andApplied Chemistry, are the classifications recommended for discrete poresizes of less than 2 nm, from 2 nm to 50 nm, and greater than 50 nm,respectively. Thus, while the (a) porous particles can include discretepores of all sizes and shapes (that is, discrete pores entirely withinthe continuous polymeric phase) providing a suitable volume in eachdiscrete pore, macro discrete pores are particularly useful. While therecan be open macro pores on the surface of the porous particle, such openpores are not desirable and are present only by accident. The size ofthe (a) porous particles, their formulation, and manufacturingconditions are the primary controlling factors for discrete pore size.However, typically the discrete pores independently have an average sizeof at least 100 nm and up to and including 7,000 nm, or more likely atleast 200 nm and up to and including 2,000 nm. Whatever the size of thediscrete pores, they are generally distributed randomly throughout thecontinuous polymeric phase. If desired, the discrete pores can begrouped predominantly in one part (for example, “core” or “shell”) ofthe (a) porous particles.

The (a) porous particles used in this invention generally have aporosity of at least 20 volume % and up to and including 70 volume %, orlikely at least 35 volume % and up to and including 65 volume %, or moretypically at least 40 volume % and up to an including 60 volume %, allbased on the total porous particle volume. Porosity can be measured by amodification of the known mercury intrusion procedure.

Glass transition temperatures of the organic polymers used to preparethe continuous polymeric phase, or the inorganic or organic spacerparticles, can be measured using Differential Scanning calorimetry (DSC)using known procedures. For many commercially available organicmaterials, the glass transition temperatures are known from thesuppliers.

Polymer viscosity (in centipoise or mPa-sec) comprising the continuouspolymeric phase can be measured in ethyl acetate at concentration of 20weight % of the polymer at 25° C. in an Anton Parr MCR 301 stressrheometer in a coquette using steady shear sweeps. Shear rate at 100sec⁻¹ was calculated from the resulting graphical plot of viscosity vs.shear rate.

CIELAB L*, a*, and b* values described herein have the known definitionsaccording to CIE 1976 color space or later known versions of color spaceand are determined using a standard D65 illuminant and known procedures.These values can be used to express a color as three numerical, L* forthe lightness (or brightness) of the color, a* for the green-redcomponent of the color, and b* for the blue-yellow component of thecolor values.

Delta E (ΔE) is a metric for understanding how the human eye perceivescolor difference or a measure of change in visual perception of twogiven colors. Moreover, ΔE is a color difference metric that is intendedto correlate with human visual judgments of small differences inperceived color between two color stimuli. ΔE values vary from 0 to 100where a value of 100 represents colors that are the exact opposite inthe CIELAB color space. Delta E 2000 (or ΔE 2000) values are obtainedfrom equations where the weighting of L* is varied depending on where inthe lightness range the color falls.

“Openness” (Openness Factor, or OF) refers to how tight the weave is ina fabric material (or other substrate material), or the percentage ofholes in a fabric construction, and is sometimes referred to as “weavedensity.” The lower the OF, the less the light transmittance and thegreater the visible light that is obstructed or blocked. It is the ratiobetween transparent and opaque surfaces and depends on the spacing anddimension of the yarn.

Unless otherwise indicated herein, the terms “first opposing surface”and “second opposing surface” refer to the opposing surfaces of thesubstrate (described below) used to form a foamed, opacifying elementaccording to the present invention. The terms “first outer surface” and“second outer surface” refer to the opposing outer surfaces of a foamed,opacifying element formed according to the present invention.

Uses

The foamable aqueous compositions, foamed aqueous compositions, andfunctional composition formulations described herein can be used toprepare foamed, opacifying elements that in turn can be useful asradiation (“light”) blocking materials or blackout materials for variousenvironments and structures. The foamed, opacifying elements can alsoexhibit improved sound and heat blocking properties. The foamed,opacifying elements exhibit blackout or light-blocking properties andcan optionally have a printable outer surface capable of being embossedor accepting ink used in screen printing, gravure printing, inkjetprinting, thermal imaging (such as “dye sublimation thermal transfer”),or other imaging processes. Thus, one can provide embossable orprintable surfaces in such foamed, opacifying elements so that theprinted image on one outer surface is generally not observable from theother outer surface.

Foamable Aqueous Compositions

The foamable aqueous compositions described herein can be suitablyaerated (or “foamed”) to provide foamed aqueous compositions, forexample to prepare a foamed, opacifying element according to the presentinvention as described below. In many embodiments, each foamable aqueouscompositions used in the present invention have five essentialcomponents, that is, only five components are needed to obtain theproperties of the dry opacifying layer in a foamed, opacifying elementdescribed herein: (a) porous particles as described below; (b) a bindermaterial (that is transformed into (b′) matrix material), also describedbelow; (c) one or more additives as described below, for examplecomprising at least one surfactant; (d) water; and (e) an opacifyingcolorant that is a different material from all of the additives ofcomponent (c). This opacifying colorant is chosen to absorbelectromagnetic radiation generally in the UV and visible regions of theelectromagnetic spectrum, for example, wavelengths of at least 250 nmand up to and including 800 nm or of at least 350 nm and up to andincluding 700 nm.

The foamable aqueous composition generally has at least 35% and up toand including 70% solids, or more particularly at least 40% and up toand including 60% solids.

(a) Porous Particles:

Porous particles used in the present invention containing discrete pores(or compartments or voids) are used in the opacifying layers and theyare generally prepared using one or more water-in-oil emulsions incombination with an aqueous suspension process, such as in theEvaporative Limited Coalescence (ELC) process that is known in the art.The details for the preparation of the (a) porous particles areprovided, for example, in U.S. Pat. No. 8,110,628 (Nair et al.), U.S.Pat. No. 8,703,834 (Nair), U.S. Pat. No. 7,754,409 (Nair et al.), U.S.Pat. No. 7,887,984 (Nair et al.), U.S. Pat. No. 8,329,783 (Nair et al.),and U.S. Pat. No. 8,252,414 (Putnam et al.), the disclosures of all ofwhich are incorporated herein by reference. Thus, the (a) porousparticles are generally polymeric and organic in nature (that is, thecontinuous polymeric phase is polymeric and organic in nature) andnon-porous particles (having less than 5% porosity) are excluded fromuse in the present invention. Inorganic particles can be present on theouter surface as noted below.

The (a) porous particles are composed of a continuous polymeric phasederived from one or more organic polymers that are chosen so that thecontinuous polymeric phase has a glass transition temperature (T_(g)) ofgreater than 80° C., or more typically of at least 100° C. and up to andincluding 180° C., or more likely at least 110° C. and up to andincluding 170° C. as determined using Differential Scanning calorimetry.Polymers having a T_(g) that is greater than 200° C. are typically lessuseful in the continuous polymeric phase.

In addition, the continuous polymeric phase can comprise one or moreorganic polymers, each of which has a viscosity of at least 80centipoises (80 mPa-sec) and up to and including 500 centipoises (500mPa-sec) at a shear rate of 100 sec⁻¹ as measured in ethyl acetate at aconcentration of 20 weight % at 25° C.

For example, the continuous polymeric phase can comprise one or moreorganic polymers having the properties noted above, wherein generally atleast 70 weight % and up to and including 100 weight % based on thetotal polymer weight in the continuous polymeric phase, is composed ofone or more cellulose polymers (or cellulosic polymers) including butnot limited to, those cellulosic polymers derived from one or more (forexample, a combination) of cellulose acetate, cellulose butyrate,cellulose acetate butyrate, and cellulose acetate propionate. A polymerderived solely from cellulose acetate butyrate is particularly useful.Mixtures of these cellulose polymers can also be used if desired, andmixtures comprising a polymer derived from cellulose acetate butyrate asat least 80 weight % of the total of cellulose polymers (or of allpolymers in the continuous polymeric phase) are particularly usefulmixtures.

In general, the (a) porous particles used in the present invention havea mode particle size equal to or less than 50 μm, or of at least 2 μmand up to and including 50 μm, or typically of at least 3 μm and up toand including 30 μm or even up to and including 40 μm. Most useful (a)porous particles have a mode particle size of at least 3 μm and up toand including 20 μm. Mode particle size represents the most frequentlyoccurring diameter for spherical particles and the most frequentlyoccurring largest diameter for the non-spherical particles in a particlesize distribution histogram, which can be determined using knownequipment (including light scattering equipment such as the Sysmex FPIA3000 Flow Particle Image Analyzer that used image analysis measurementsand that can be obtained from various sources including MalvernPanalytical; and coulter counters and other particle characterizingequipment available from Beckman Coulter Diagnostics), software, andprocedures.

Pore stabilizing materials such as hydrocolloids can be present withinat least part of the volume of the discrete pores distributed throughoutthe continuous polymeric phase, which pore stabilizing materials aredescribed in the Nair, Nair et al., and Putnam et al. patents citedabove. In some embodiments, the same pore stabilizing material isincorporated in essentially all the discrete pores throughout the entire(a) porous particles. The pore stabilizing hydrocolloids can be selectedfrom the group consisting of carboxymethyl cellulose (CMC), a gelatin orgelatin derivative, a protein or protein derivative, polyvinyl alcoholand its derivatives, a hydrophilic synthetic polymer, and awater-soluble microgel.

It can be desired in some embodiments to provide additional stability ofone or more discrete pores in the (a) porous particles during theirformation, by having one or more amphiphilic block copolymers disposedat the interface of the one or more discrete pores and the continuouspolymeric phase. Such materials are “low HLB,” meaning that they have anHLB (hydrophilic-lipophilic balance) value as it is calculated usingknown science, of 6 or less, or even 5 or less. The details of theseamphiphilic polymers and their use in the preparation of the (a) porousparticles are provided in U.S. Pat. No. 9,029,431 (Nair et al.), thedisclosure of which is incorporated herein by reference.

A particularly useful amphiphilic block copolymer useful in suchembodiments comprises poly(ethyleneoxide) and poly(caprolactone) thatcan be represented as PEO-b-PCL. Amphiphilic block copolymers, graftcopolymers and random graft copolymers containing similar components arealso useful.

Such an amphiphilic block copolymer can be generally present in the (a)porous particles in an amount of at least 1 weight % and up to andincluding 99.5 weight %, or at least 2 weight % and up to and including50 weight %, based on total porous particle dry weight.

The (a) porous particles used in this invention can be spherical ornon-spherical depending upon the desired use. In a method used toprepare the (a) porous particles, additives (shape control agents) canbe incorporated into the first or second aqueous phases, or in the oil(organic) phase to modify the shape, aspect ratio, or morphology of the(a) porous particles. The shape control agents can be added prior to orafter forming the water-in-oil-in-water emulsion. In either case, theinterface at the oil and second water phase is modified before organicsolvent is removed, resulting in a reduction in sphericity of the (a)porous particles. The porous particles can also comprise surfacestabilizing agents, such as colloidal silica, on the outer surface ofeach (a) porous particle, in an amount of at least 0.1 weight %, basedon the total dry weight of the (a) porous particle.

The average size of the discrete pores in the (a) porous particles isdescribed above.

The (a) porous particles can be provided as powders, or as aqueoussuspensions (including water or water with water-miscible organicsolvents such as alcohols). Such powders and aqueous suspensions canalso include surfactants or suspending agents to keep the porousparticles suspended or for rewetting them in an aqueous medium. A usefulsurfactant for this purpose, for example, is a C₁₂-C₁₄ secondary alcoholderivative of poly(ethylene oxide) that can be commercially available asTERGITOL® 15-S-7 (Dow Chemical Corporation). The other compositionalfeatures are described in the incorporated description of methods forpreparing the (a) porous particles.

The (a) porous particles are generally present in the foamable aqueouscomposition in an amount of at least 0.05 weight % and up to andincluding 20 weight %, or typically at least 0.5 weight % and up to andincluding 15 weight %, based on the total weight of the foamable aqueouscomposition (including all solvents that are present), particularly whenthe (a) porous particles have a mode size of at least 3 μm and up to andincluding 20 μm.

Optimal dry opacifying layers designed according to the presentinvention comprise: (a) porous particles containing a small amount of an(e) opacifying colorant as described below to enhance the light blockingcapacity of the (a) porous particles (particularly transmitted lightblocking capacity); a (b′) matrix material derived from a (b) bindermaterial to hold the (a) porous particles in place; and (c) surfactantsand other additives including optionally one or more tinting colorantsthat can be in other (a) porous particles or dispersed within the layer.The foamed aqueous composition used to prepare the dry opacifying layercomprises foam cells that surround the (a) porous particles.

Upon drying the foamed aqueous composition, the large mismatch inrefractive index between the discrete pores of the (a) porous particlesin the dry opacifying layer and the polymer walls (continuous polymericphase), and the dried foam cells, causes incident electromagneticradiation passing through the dry opacifying layer to be scattered bythe multiplicity of interfaces and discrete pores. The back scatteredelectromagnetic radiation can again be scattered and returned in thedirection of the incident electromagnetic radiation thus reducing theattenuation and contributing to the opacifying power and brightness orluminous reflectance of the opacifying layer. If a small amount of (e)opacifying colorant is present in the (a) porous particles of the dryopacifying layer, for example either in the discrete pores or in thecontinuous polymer phase of the (a) porous particles, the opacifyingpower of the dry opacifying layer is increased. This is because themultiple scattering of electromagnetic radiation in the dry opacifyinglayer increases the path length of the electromagnetic radiation throughthe opacifying layer, thereby increasing the chance that theelectromagnetic radiation will encounter the opacifying colorant in thedry opacifying layer and be blocked or absorbed by it.

A single dry opacifying layer can be present in embodiments according tothe present invention comprises (a) porous particles and a relativelylow amount of an (e) opacifying colorant such as carbon black forcreating light-blocking coatings and the dry foam cells surrounded bythe (b′) matrix material. Multiple light scattering effects by and amongthe (a) porous particles and the surrounding dry foam cells, increasethe path of the electromagnetic radiation through the dry opacifyinglayer. The likelihood of electromagnetic radiation encountering an (e)opacifying colorant is increased by this greater path length.

(b) Binder Materials:

The foamable and foamed aqueous compositions used in the present alsocomprises one or more (b) binder materials from which a binding (b′)matrix material can be formed to hold the (a) porous particles, (c)additives, and (e) opacifying colorants together in a dry opacifyinglayer.

It is particularly useful that the (b) binder material have thefollowing properties: it is water-soluble or water-dispersible; it iscapable of forming a stable foamed aqueous composition with theessential and optional components described herein; it is capable ofbeing disposed onto a suitable substrate as described below; it does notinhibit the aeration (foaming) process (described below); it is capableof being dried and where desired also crosslinked (or cured); it hasgood light and heat stability; and it is film-forming but upon curing,it contributes to the flexibility of the foamed, opacifying element andis thus not too brittle, for example having a T_(g) of less than 25° C.as determined using Differential Scanning calorimetry.

The choice of (b) binder material can also be used to increase thecleanability of the resulting foamed opacifying compositions in thefoamed, opacifying elements. The (b) binder material can be used toprovide the (b′) matrix material that adds to a supple feel to touch andflexibility especially when disposed on a porous substrate (for example,a fabric) that is meant for window coverings such as draperies.

The (b) binder material can include one or more organic polymers thatare film forming and that can be provided as an emulsion, dispersion, oran aqueous solution, and that cumulatively provide the properties notedabove. It can also include polymers that are self-crosslinking orself-curable, or it can include one or more polymers to whichcrosslinking agents are added and are thus curable or capable of beingcrosslinked (or cured) under appropriate conditions.

Thus, if the (b) binder material is crosslinkable (or curable) in thepresence of a suitable crosslinking agent or catalyst, such crosslinking(or curing) can be activated chemically with heat, radiation, or otherknown means. A curing or crosslinking process serves to provide improvedinsolubility of the resulting dry foamed composition and well ascohesive strength and adhesion to the porous substrate. The curing orcrosslinking agent is generally a chemical having functional groupscapable of reacting with reactive sites in a (b) binder material (suchas a functionalized latex polymer) under curing conditions to therebyproduce a crosslinked structure. Representative crosslinking agentsinclude but are not limited to, multi-functional aziridines, aldehydes,methylol derivatives, and epoxides.

Useful (b) binder materials include but are not limited, to poly(vinylalcohol), poly(vinyl pyrrolidone), ethylene oxide polymers,polyurethanes, urethane-acrylic copolymers, other acrylic polymers,styrene polymers, styrene-acrylic copolymers, vinyl polymers,vinyl-acrylic polymers, styrene-butadiene copolymers, acrylonitrilecopolymers, polyesters, silicone polymers, or a combination of two ormore of these organic polymers. Such binder materials are readilyavailable from various commercial sources or can be prepared using knownstarting materials and synthetic conditions. The binder material can beanionic, cationic or nonionic in net charge. A useful class offilm-forming (b) binder materials includes aqueous latex polymerdispersions such as acrylic latexes (including acrylic copolymers) thatcan be ionic or nonionic colloidal dispersions of acrylate polymers andcopolymers. For example, useful film-forming aqueous latexes include butare not limited to, styrene-butadiene latexes, poly(vinyl chloride) andpoly(vinylidene chloride) latexes, poly(vinyl pyridine) latexes,poly(acrylonitrile) latexes, poly(vinyl chloride)-acrylic copolymers,and latexes formed from N-methylol acrylamide, butyl acrylate, and ethylacrylate.

The (b) binder material generally has a glass transition temperaturethat is less than 25° C., more likely equal to or less than −10° C., oreven equal to or less than −25° C. Glass transition temperature forthese materials can be determined using known procedures such asDifferential Scanning calorimetry as described above. The (b) bindermaterial desirably has adequate flexibility and tensile strength inorder to maintain integrity upon handling.

The one or more (b) binder materials can be present in the foamableaqueous composition in an amount of at least 15 weight %, or at least 20weight % and up to and including 70 weight %, or typically at least 30weight % and up to and including 50 weight %, based on the totalfoamable aqueous composition (that is, the total weight of allcomponents including all solvents).

(c) Additives:

The foamable aqueous compositions can include at least 0.0001, or atleast 0.001 weight %, or even at least 0.01 weight %, and up to andincluding 2 weight %, or up to and including 5 weight %, or even up toand including 20 weight %, or even at least and including 30 weight % ofone or more (c) additives, or more likely of (c) two or more additives,and typically such (c) two or more additives can comprise at least onefoaming agent and at least one foam stabilizing agent as defined below.These amounts refer to the total of all the (c) additives in eachfoamable aqueous composition and are based on the total weight of thosecompositions (including water). There can be mixtures of each type of(c) additive, or mixtures of two or more types of (c) additives in eachof the foamable aqueous compositions.

Any of these (c) additives or mixtures thereof, can be present withinany location of the foamed aqueous composition, including but notlimited to the continuous polymeric phase; a volume of the first set (orother set) of discrete pores; or both the first set (or other set) ofdiscrete pores and the continuous polymeric phase of the (a) porousparticles. Alternatively, the (c) additives can be present within the(b) binder material alone, or both within the (b) binder material andwithin the (a) porous particles.

In all embodiments, the (c) additives useful in the present inventionare not the same compounds or do not have the same function as the (a)porous particles, (b) binder materials, and (e) opacifying colorants asdescribed herein.

Useful (c) additives include but are not limited to plasticizers,inorganic or organic pigments and dyes (for example, pigment or dyecolorants different from the opacifying colorants described below),flame retardants, biocides (such as fungicides and antimicrobialagents), preservatives, pH buffers, optical brighteners, tintingcolorants, metal particles such as metal platelets or metal flakes,thickeners, various surfactants, and inert inorganic or organic fillers(such as clays) that are not any of the other materials or opacifyingcolorants described below.

The “inert” inorganic or organic fillers are particles that can be addedto reduce the use of more expensive (b) binder materials. Such fillersdo not undergo a chemical reaction in the presence of water or othercomponents in the foamable aqueous composition; nor do they absorbsignificant electromagnetic radiation like the (e) opacifying colorants.Useful inert organic or inorganic filler materials include but are notlimited to titanium dioxide, talc, clay (for example, kaolin), magnesiumhydroxides, aluminum hydroxides, dolomite, glass beads, silica, mica,glass fibers, nano-fillers, and calcium carbonate. Combinations of thesematerials can be used if desired. A clay, talc, calcium carbonate, or amixture of any of these materials is particularly useful.

One or more plasticizers can be added to soften the “hand” of the finalfoamed, opacifying element. Useful plasticizers include but are notlimited to, alkyl sulfonic acid of phenol sold under the name MESSAMOL®(Lanxess Chemical, Inc.) and bis(2-ethylhexyl) terephthalate sold underthe name EASTMAN® 168 (Eastman Chemical Co.).

At least one (c) additive (and more likely at least two differentadditives) can be a surfactant that is defined as a compound thatreduces surface tension. In most embodiments, at least one usefulsurfactant is a foaming agent (or foaming surfactant) that functions tocreate and enhance foam formation. In many embodiments, the (c)additives comprise one or more foaming agents (foaming surfactants) aswell as one or more foam stabilizing agents that are also surface-activeagents that function to structure and stabilize the foam. Examples ofuseful foaming agents (foaming surfactants) and foam stabilizing agentsinclude but are not limited to, ammonium stearate, sodium laurylsulfate, ammonium lauryl sulfate, ammonium sulfosuccinate, disodiumstearyl sulfosuccinate, diammonium n-octadecyl sulfosuccinamate,ethoxylated alcohols, ionic, nonionic or anionic agents such as fattyacid soaps or a fatty acid condensation product with an alkylene oxide,for example, the condensation product of ethylene oxide with lauryl oroleic acid or an ester of fatty alcohols and similar materials, many ofwhich can be obtained from various commercial sources. Mixtures offoaming agents (or foaming surfactants) and mixtures of foam stabilizerscan be used if desired.

The relative amounts of each of these two types of (c) additives is notcritical if the desired function is evident, that is suitable foamingproperties as required to prepare the foamed aqueous composition, andstability of the foamed aqueous composition during storage andmanufacture of the foamed, opacifying elements. The optimal amounts ofeach of these (c) additives can be determined by using routineexperimentation.

Other useful (c) additives include metal particles that can be obtainedfrom any available commercial source as metal flakes or metal plateletsand in dry form or as a suspension. Such metal flakes or metal plateletsare substantially 2-dimensional particles, having opposing surfaces orfaces separated by a relatively minor thickness dimension. The metalflakes can have a size range of at least 2 μm and up to and including 50μm in main surface equivalent circular diameter (ECD) wherein the ECD isthe diameter of a circle having the same area as the main face. Examplesof useable metal flakes include those available from Ciba SpecialtyChemicals (BASF) such as aluminum flakes that are available as METASHEEN91-0410 in ethyl acetate, and copper flakes that can be obtained fromvarious commercial sources. Further details of useful metal flakes areprovided in Cols. 11-12 of U.S. Pat. No. 8,614,039 (Nair et al.), thedisclosure of which is incorporated herein by reference. The metalparticles described above, and particularly the metal flakes, can be inthe foamable aqueous composition in any suitable location but they areparticularly useful when incorporated within the (a) porous particlessuch as within the volume of the discrete pores of the (a) porousparticles.

Useful biocides (that is, antimicrobial agents or antifungal agents)that can be present as (c) additives include but are not limited to,silver metal (for example, silver particles, platelets, or fibrousstrands) and silver-containing compounds such as silver chelates andsilver salts such as silver sulfate, silver nitrate, silver chloride,silver bromide, silver iodide, silver iodate, silver bromate, silvertungstate, silver phosphate, and silver carboxylates. In addition,copper metal (for example, copper particles, platelets, or fibrousstrands) and copper-containing compounds such as copper chelates andcopper salts can be present as (c) additives for biocidal purposes.Mixtures of any of silver metal, silver-containing compounds, coppermetal, and copper-containing compounds, can also be present and used inthis manner.

It can also be useful to include thickeners as (c) additives to modifythe viscosity of the foamable aqueous composition and to stabilize it ifaeration is not inhibited. A skilled worker can optimize the viscosityto obtain optimal aeration conditions and desired foam density asdescribed below. Useful thickeners can be utilized to control therheology of the foamable aqueous composition depending upon the methodused to form the dry opacifying layer on a substrate as described below.Particularly useful rheology modifiers are RHEOVIS® PU 1214 (BASF),ACRYSOL® G111 (Dow Chemical Company), and Paragum (Royal Adhesives,Inc.).

Useful (c) additives can comprise one or more tinting colorants that canbe suitable dyes or pigments (or combinations) and can be used toprovide a specific observable color, coloration, or hue in the resultingfoamed, opacifying elements. These materials are not chosen to providethe opacifying property described below for the (e) opacifying colorantsand thus, tinting colorants are intended to be different materials thanthe (e) opacifying colorants. Mixtures of tinting colorants can bepresent in the foamable aqueous compositions and they can be differentin composition and amount from each other. The desired coloration or huecan be obtained using specific tinting colorants can be used incombination with (e) opacifying colorant(s) described below to offset ormodify the original color of a foamed, opacifying element (without suchmaterials) to provide more whiteness (or brightness or increased L*) inthe final “color” (or coloration). The one or more tinting colorants canbe incorporated within the (a) porous particles (either within thevolume of discrete pores, within the continuous polymeric phase, or inboth places), or they can be uniformly dispersed within the (b) bindermaterial. In some embodiments, a tinting colorant can be incorporatedwithin the same (a) porous particles that also include an (e) opacifyingcolorant (as described below). Alternatively, one or more tintingcolorants can be present within both the (a) porous particles (in asuitable location) and within the (b) binder material.

The one or more tinting colorants can be present in the foamable aqueouscomposition in an amount of at least 0.0001 weight %, or more typicallyat least 0.001 weight % and up to and including 3 weight %, based on thetotal weight of the foamable aqueous composition (including allsolvents). Tinting colorants can be dyes or organic pigments that aresoluble or dispersible in organic solvents and polymers that are usedfor making the (a) porous particles and thus can be included within theoil phase used to prepare such (a) porous particles. Alternatively, thetinting colorants can be primarily water-soluble or water-dispersiblematerials that are included into an aqueous phase used to prepare the(a) porous particles or they can be added directly to the foamableaqueous composition.

It can also be useful to include one or more optical brighteners as (c)additives to increase the whiteness (brightness, L*, or “fluorescent”effect) of the final coloration in the foamed, opacifying element.Optical brighteners are sometimes known in the art as “fluorescentwhiteners” or “fluorescent brighteners.” In general, such materials areorganic compounds selected from classes of known compounds such asderivatives of stilbene and 4,4′-diaminostilbene (such as bistriazinylderivative); derivatives of benzene and biphenyl (such as styrilderivatives); pyrazolines; derivatives of bis(benzoxazole-2-yl);coumarins; carbostyrils; naphthalimides; s-triazines; andpyridotriazoles. Specific examples of optical brighteners can be foundin various publications including “Fluorescent Whitening Agents,”Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, volume11, Wiley & Sons, 1994. One of more of such compounds can be present inan amount of at least 0.01 weight % and up to and including 2 weight %,all based on the total weight of the foamable aqueous composition.

When present, one or more optical brighteners can be in one or morelocations in the foamed aqueous composition. For example, an opticalbrightener can be present in the (b) binder material, or within thecontinuous polymeric phase of the (a) porous particles; a volume of thefirst set (or any other set) of discrete pores in the (a) porousparticles; or both in a volume of the first set (or any other set) ofdiscrete pores and the continuous polymeric phase, of the (a) porousparticles.

The (c) additives can comprise two or more materials selected fromsurfactant that is a foaming agent (foaming surfactant), a foamstabilizing agent, a flame retardant, an antimicrobial agent, and aninorganic filler (such as a clay or titanium dioxide).

(d) Aqueous Medium:

Water is the primary solvent used in an (d) aqueous medium in thefoamable aqueous compositions according to the present invention. By“primary” is meant that of the total weight of solvents, water comprisesat least 75 weight %, and more likely at least 80 weight % and up to andincluding 100 weight % of the total solvent weight. Auxiliary solventsthat can be present must not adversely affect or harm the othercomponents in the composition, namely the (a) porous particles, (b)binder materials, (c) one or more additives, and (e) opacifying agents.Nor must such auxiliary solvents adversely affect formation of thefoamable aqueous composition or its use to prepare a foamed, opacifyingelement. Such auxiliary solvents can be water-miscible organic solventssuch as alcohols and ketones.

The (d) aqueous medium then, which is primarily water, comprises atleast 30 weight % and up to and including 65 weight %, or typically atleast 40 weight % and up to and including 60 weight %, of the totalweight of the foamable aqueous composition.

(e) Opacifying Colorants:

The (e) opacifying colorants used in the present invention can be asingle material or chosen from any suitable combination of materialssuch that the single or multiple materials absorb UV and visibleelectromagnetic radiation (defined above) to provide blackout properties(or suitable opacity). (e) Opacifying colorants can be soluble dyes orpigments or combinations of each or both types of materials. The (e)opacifying colorants are different compositional and functionally fromthe compounds defined above as the (c) additives.

In most embodiments, the one or more (e) opacifying colorants arepresent within a volume of the first set (or another set) of discretepores within the (a) porous particles, within the continuous polymericbinder of the (a) porous particles, or within both the volume of thefirst set (or another set) of discrete pores and the continuouspolymeric binder of the (a) porous particles. This is highlyadvantageous as the (a) porous particles can be used to “encapsulate”various (e) opacifying colorants as well as tinting colorants or other(c) additives so they are kept isolated from the other components of thefoamable aqueous composition and are additionally not exposed to theenvironment during sewing or upon surface damage of the foamed,opacifying element. However, in some embodiments, it can be useful toincorporate (e) opacifying colorants solely or additionally within the(b) binder material in which the (a) porous particles are dispersed.

As used herein, an (e) opacifying colorant can include one or morecolorant materials that are chosen, individually or in combination, toprovide the blocking or absorption of electromagnetic radiation (asdescribed above). While the (e) opacifying colorant(s) can provide somecoloration or desired hue, they are not purposely chosen for thatpurpose and are thus materials that are chosen to be different from thetinting colorants described above.

Examples of (e) opacifying colorants that can be used individually or incombination include but are not limited to, neutral or black pigments ordyes, a carbon black, black iron oxide, graphite, aniline black,anthraquinone black, and combinations of colored pigments or dyes suchas combinations of two or more cyan, magenta, green, orange, blue, red,and violet dyes. The present invention is not limited to only thespecific opacifying colorants described herein but these are consideredas representative and as suitable guidance for a skilled worker tochoose other opacifying colorants for the desired purpose. A carbonblack, a neutral or black pigment or dye (or combination thereof), or acombination of pigments or dyes other than carbon black, is particularlyuseful as an opacifying colorant, of which there are many typesavailable from commercial sources. Combinations of dyes or pigments suchas a combination of the subtractive primary colored pigments (cyan,magenta, and yellow colored pigments) can also be used to provide avisually neutral (e) opacifying colorant.

The (e) opacifying colorant can be generally present in the foamableaqueous composition in an amount of at least 0.001 weight % and up toand including 0.5 weight %, or even at least 0.003 weight % and up toand including 0.2 weight %, all based on the total weight of thefoamable aqueous composition (including the weight of all solvents).These amounts refer to the total amount of one or a mixture of (e)opacifying colorants.

In some embodiments, the (e) opacifying colorant is a carbon black thatis present in an amount of at least 0.003 weight % and up to andincluding 0.2 weight %, based on the total weight of the foamableaqueous composition.

If the (e) opacifying colorants are in pigment form, they can be milledto a fine particle size using appropriate pigment dispersants, and thenencapsulated within the volume of the discrete pores of the (a) porousparticles by incorporating the milled pigment within an aqueous phaseused in making the (a) porous particles. Preparation of milled solidparticle dispersions can include combining the (e) opacifying colorantparticles to be reduced in size with a dispersant and a liquid mediumsuch as water or ethyl acetate [when the (e) opacifying colorant isincorporated in the continuous polymeric phase] in which the (a) porousparticles are to be dispersed, in a suitable grinding mill in which the(a) porous particles are reduced in size and dispersed. The dispersant,an important ingredient in the milling, can be chosen to allow the (e)opacifying colorant particles to be milled in the liquid medium down toa size small enough for incorporation into the discrete pores of theporous particles. The dispersants can be selected to obtain efficient(e) opacifying colorant particle size reduction during milling, providegood colloidal stability of the (e) opacifying colorant particles toprevent agglomeration after milling and impart the desired properties ofthe final foamed aqueous composition containing the (e) opacifyingcolorants and the (a) porous particles containing them.

Alternatively, the (e) opacifying colorant can be incorporated withinthe continuous polymeric phase of the (a) porous particles byincorporating the (e) opacifying colorant in the oil phase used inmaking the porous particles. Such arrangements can be achieved duringthe manufacture of the (a) porous particles using the teaching providedherein and in references cited herein.

Foamed Aqueous Compositions

Foamed aqueous compositions can be prepared using the proceduresdescribed below wherein an inert gas (such as air) is mechanicallyincorporated into the foamable aqueous composition as described above,which procedures are designed to provide a foam density of at least 0.1g/cm² and up to and including 0.5 g/cm³, or more likely of at least 0.15g/cm³ and up to and including 0.4 g/cm³. Foam density can be determinedgravimetrically by weighing a known volume of the foamed aqueouscomposition.

The resulting foamed aqueous composition according to this inventiongenerally has at least 35% solids and up to and including 70% solids, ormore particularly at least 40% solids and up to and including 60%solids.

Components (a) through (e) of the foamed aqueous composition aregenerally present in the same relative amounts as described for thefoamable aqueous composition (described above) as the foaming processdoes not appreciably add to or diminish the relative amounts of suchcomponents.

For example, the (a) porous particles (as described above) can bepresent in the foamed aqueous composition in an amount of at least 0.05weight % and up to and including 15 weight %, or typically of at least0.5 weight % and up to and including 10 weight %, based on the totalweight of the foamed aqueous composition (including all solvents).

One or more (b) binder materials (as described above) can be present inan amount of at least 15 weight %, or at least 20 weight % and up to andincluding 70 weight % or typically of at least 30 weight % and up to andincluding 50 weight %, based on the total weight of the foamed aqueouscomposition (including all solvents).

One or more (c) additives (or two or more different additives, asdescribed above) can be present in an amount of at least 0.0001 weight %and up to and including 30 weight % or typically of at least 0.001weight %, or even at least 0.01 weight %, and up to and including 20weight %, based on the total weight of the foamed aqueous composition(including all solvents). At least one of the (c) additives can be asurfactant as described above, and the (c) additives can comprise afoaming agent (foaming surfactant) and a foam stabilizing agent. In someparticularly useful embodiments of the foamed aqueous composition, the(c) additives comprise two or more materials selected from surfactantthat is a foaming agent (foaming surfactant), a surfactant that is afoam dispersing agent, a flame retardant, an antimicrobial agent, and aninert organic or inorganic filler (such as a clay and titanium dioxide).

Water can also be present as the predominant solvent (at least 75 weight% of total solvent weight), and all the solvents in an (d) aqueousmedium can be present in an amount of at least 30 weight % and up to andincluding 70 weight %, or typically at least 40 weight % and up to andincluding 60 weight %, based on the total weight of the foamed aqueouscomposition.

The (e) opacifying colorants (as described above) are generally presentin any suitable amount to provide the desired appearance, coloration,and opacity in the resulting foamed, opacifying element, In manyembodiments, the one or more (e) opacifying colorants can be present inan amount of at least 0.001 weight % or at least 0.001 weight % and upto and including 0.5 weight %, or even in an amount of least 0.003weight % and up to and including 0.2 weight %, especially when the (e)opacifying colorant is a carbon black, all weights based on the totalweight of the foamed aqueous composition (including all solvents).

For example, an opacifying colorant can be a carbon black and present inan amount of at least 0.003 weight % and up to and including 0.2 weight% based on the total weight of the foamed aqueous composition. Such (e)opacifying colorant can be present in any desirable location as notedabove.

Foamed, Opacifying Elements

Foamed, opacifying elements can be prepared using methods describedbelow according to the present invention. Such articles comprise asubstrate, a dry opacifying layer formed on the first opposing surfacein a manner described below, and a functional composition disposed over(or directly on in some embodiments) the dry opacifying layer, forexample as a functional layer, as described below. Each substrate usefulherein generally has two opposing sides, for example, a first opposingsurface (or side) and a second opposing surface (or side), whichopposing surfaces are generally planar in form.

In specific embodiments, the foamed, opacifying elements preparedaccording to this invention are designed with a single dry opacifyinglayer as the only foamed layer disposed directly on only one (such asthe first) opposing surface of the substrate. In such cases, the singledry opacifying layer and the functional composition disposed thereon arethe only essential layers or compositions in the foamed, opacifyingelement. This simplified structure has numerous advantages over themulti-layer structures known in the art where an opacifying colorant ina foamed layer is generally sandwiched between other foamed layershaving various pigments or particulate fillers, such as described forexample, in U.S. Pat. No. 4,677,016 (noted above).

However, some less desirable foamed, opacifying elements can be designedwith multiple foamed layers including a single dry opacifying layer. Amultiple-layer structure can for example, comprise a single dryopacifying layer sandwiched having a foamed non-opacifying layers(having no opacifying colorant as described herein or other pigments).

The dry opacifying layer can be derived from a foamed aqueouscomposition described above, and comprises components (a) porousparticles, (b′) matrix material derived from (b) binder material, (c)one or more additives, (d) aqueous medium, and (e) opacifying colorant,all of which are described in more detail above.

Component (a) porous particles that are present in an amount of at least0.1 weight % and up to and including 35 weight % or at least 0.5 weight% and up to and including 25 weight % are described in detail above, theamounts based on the total weight of the dry opacifying layer. The (a)porous particles can have a mode particle size of at least 2 μm and upto and including 50 μm (or at least 3 μm and up to and including 30 μm,or more likely at least 3 μm and up to and including 20 μm) and a firstset of discrete pores of the (a) porous particles can have an averagepore size of at least 100 nm and up to and including 7,000 nm.

In addition, the dry opacifying layer includes a (b′) matrix materialthat is derived from a (b) binder material upon curing, which (b′)matrix material is generally present in an amount of at least 10 weight% and up to and including 80 weight %, or at least 20 weight % and up toand including 60 weight %, based on the total weight of the dryopacifying layer. Such (b′) matrix materials are at least partiallycured or crosslinked as described below and can be cured up to 100% ofall potential curable or crosslinking sites in the (b) binder material.

One or more (c) additives can be present in an amount of at least 0.0001weight % and up to and including 50 weight %, or at least 1 weight % andup to and including 45 weight %, such (c) one or more additives beingselected from the group consisting of foaming agents, foam stabilizingagents, dispersants, plasticizers, inorganic or organic pigments anddyes (for example, pigment or dye colorants different from theopacifying colorants described below), flame retardants, biocides(including antimicrobials and fungicides), preservatives, pH buffers,surfactants, metal particles such as metal platelets or metal flakes,thickeners, and inert inorganic or organic fillers (such as clays andtitanium dioxide) that are not any of the other materials or (e)opacifying colorants described herein, all of which (c) additives aredescribed in more detail above. The amounts are based on the totalweight of the opacifying layer. As noted above, embodiments can includeat least one surfactant that is a foaming agent and at least one foamstabilizing agent.

Particularly useful (c) additives can comprise one or more materialsselected from a foaming agent (foaming surfactant), a foam stabilizingagent, a flame retardant, a biocide (such as an antimicrobial agent),and inert inorganic or organic fillers (such as a clay and titaniumdioxide). A useful biocide can comprise silver metal or a silver salt.

The opacifying layer can comprise one or more tinting colorants as (c)additives, for example in the (a) porous particles, in an amount of atleast 0.0001 weight % and up to and including 3 weight %, based on thetotal weight of the opacifying layer.

It is also useful to include one or more optical brighteners as (c)additives in an amount of at least 0.001 weight % and up to andincluding 0.4 weight %, based on the total weight of the opacifyinglayer.

Unless otherwise noted, the term “dry opacifying layer” used hereinrefers to a foamed and densified (and optionally cured) layersubstantially in dry form, that contains less than 5 weight %, or evenless than 2 weight %, of aqueous medium (including water and anyauxiliary solvents), based on the total weight of the dry foamedcomposition. This amount does not include any water that may be presentin the discrete pores of the (a) porous particles. The dry opacifyinglayer generally comprises at least 90% solids, or at least 95% or 98%solids.

The dry opacifying layer can also contain at least 0.002 weight %, oreven at least 0.02 weight % and up to and including 2 weight % or up toand including 1 weight %, of one or more (e) opacifying colorants (asdescribed above), based on the total weight of the dry opacifying layer.Such (e) opacifying colorants can be present in locations describedabove. As noted above, the (e) opacifying colorants are different incomposition and function from all other materials in the dry opacifyinglayer. The possible locations of the (e) opacifying colorant aredescribed above.

For example, a carbon black can be present as the (e) opacifyingcolorant in an amount of at least 0.002 weight % and up to and including1 weight %, based on the total weight of the dry opacifying layer.

Substrates useful in the practice of the present invention can comprisevarious porous or non-porous materials including but not limited towoven and nonwoven textile fabrics composed of nylon, polyester, cotton,aramide, rayon, polyolefin, acrylic wool, porous glasses, fiberglassfabrics, or felt or mixtures thereof, or porous polymeric films [such asporous films derived from triacetyl cellulose, polyethyleneterephthalate (PET), diacetyl cellulose, acetate butyrate cellulose,acetate propionate cellulose, polyether sulfone, polyacrylic basedresin, for example, poly(methyl methacrylate), a polyurethane-basedresin, polyester, polycarbonate, aromatic polyamide, polyolefins (forexample, polyethylene and polypropylene), polymers derived from vinylchloride (for example, polyvinyl chloride and a vinyl chloride/vinylacetate copolymer), polyvinyl alcohol, polysulfone, polyether,polynorbornene, polymethylpentene, polyether ketone,(meth)acrylonitrile], porous paper or other porous cellulosic materials,canvases, porous wood, porous plaster and other porous materials thatwould be apparent to one skilled in the art. The substrates can vary indry thickness and in many embodiments, the substrate thickness is atleast 50 μm.

Some useful substrates comprise a porous fabric comprising a plurality(at least two) continuous yarn strands woven or knitted together. Asused herein, the “yarn” comprises continuous strands (at least two) of amaterial, which strands are twisted or woven together to form a“thread.” Each yarn strand can comprise a multifilament core that isencased in a coating comprising a thermoplastic polymer.

The multifilament core can comprise multiple (at least two) filamentscomposed of naturally-occurring fibers or polymers, or of syntheticpolymers selected from the group consisting of an aramid, apolypropylene, a polyethylene, an acrylic resin, nylon, and a polyester.Alternatively, the multifilament core can comprise fiberglass asmultiple filaments. Each of the multiple filaments can be composed ofthe same material or a mixture of such materials. Alternatively, themultiple filaments can be homogenous, but filaments composed ofdifferent materials can be used in the same multifilament core.

The multifilament core can be designed to have any desirable size and ingeneral, it has an average diameter of at least 75 denier and up to andincluding 2500 denier, wherein a denier refers to 1.2 g/9000 meters of afilament.

Each filament of the multifilament core can further comprise a flameretardant, examples of which would be readily apparent to one skilled inthe art. A multifilament core can be prepared using known technology,for example as described in U.S. Patent Application Publication2007/0015426 (Ahmed et al.), the disclosure of which is incorporatedherein by reference.

The coating applied to the multifilament core can comprise one or morethermoplastic polymers, including but not limited to a polyesterelastomer, a polypropylene, a polyethylene, an ethylene octanecopolymer, a substituted or unsubstituted vinyl chloride polymer(including homopolymer and copolymers derived in part from vinylchloride), polyvinylidene fluoride, ethylene vinyl acetate, athermoplastic polyurethane, poly(tetrafluoroethylene) (PTFE), a siliconeresin, and various hot melt adhesives. Various grades or combinations ofthese materials can be used if desired. The term “thermoplastic” refersto a polymeric material or resin that changes properties when heated andcooled.

Substrates useful in this invention generally have an openness (orOpenness Factor) of 0% and up to and including 10%, or at least 1% andup to and including 10%, or of at least 5% and up to and including 10%.

The substrates can be surface treated before application of the aqueousfoamed composition by various processes including corona discharge, glowdischarge, UV or ozone exposure, flame, or solvent washing in order topromote desired adhesion and other physical properties.

Functional Composition Formulations

A functional composition according to this invention is intended toprovide the foamed, opacifying elements with one or more functionalproperties as described below. A functional composition can comprise (i)glass particles (described below) as the sole essential component.However, in some embodiments containing the (i) glass particles, a (ii)lubricant (described below) can be also present. In still otherembodiments, a (ii) lubricant and a (iii) tinting material (describedbelow) can be present together with the (i) glass particles. In stillother embodiments, (i) glass particles can be combined with a (iii)tinting material, but a (ii) lubricant is not present.

Before application, each functional composition formulation used in thepractice of this invention can comprise an aqueous dispersion of thedesired components including the (i) glass particles. For example, insome particularly useful embodiments, the functional compositionformulation, depending on its function, can comprise: (i) glassparticles such as hollow glass particles as defined below; (ii) alubricant; (iii) a tinting material; a (iv) water-soluble orwater-dispersible organic polymeric binder; a (v) crosslinking agent forthe (iv) water-soluble or water-dispersible organic polymeric binder (ifcrosslinkable); a thickener; and a coating aid such as those having ahydrophilic-lipophilic balance number of at least 5, all mixed togetherin water to form a stable aqueous dispersion.

As described in more detail below, a functional composition formulationcan be applied in a suitable manner to provide a functional compositiondisposed over (for example, directly on) the dry opacifying layer in auniform continuous manner to form a functional layer that essentiallycovers all of the substrate surface. In other embodiments, thefunctional composition can be arranged or disposed on the dry opacifyinglayer in a discontinuous manner in small or large regions on thesubstrate surface, for example by spraying, to form a regular orirregular pattern. In many embodiments, the functional composition canbe disposed directly on the opacifying layer in a uniform or patternwisemanner so that there are no intermediate materials or layers between thedry opacifying layer and the functional composition.

In some embodiments, the functional composition formulation can befoamed similarly to foaming of the foamable aqueous compositiondescribed below before it is disposed over (or directly on) the dryopacifying layer. The resulting applied functional composition is thenalso foamed.

The functional composition formulation generally has a % solids of atleast 0.5% and up to and including 10% with water being the predominant(more than 50 weight % of all solvents) solvent.

The functional composition can be present in a foamed, opacifyingelement at a dry coverage of at least 0.5 g/m² and up to and including15 g/m² or of at least 1 g/m² and up to and including 10 g/m².

The functional composition according to this invention can provide oneor more functions simultaneously. For example, it can provide one ormore of: a “release” function where the coefficient of friction betweenthe opacifying layer and any other solid surface is reduced allowingeasy separation of the contacting surfaces; an anti-blocking functionwhere microscopic protrusions or asperities help to minimize surfaceadherence between the dry opacifying layer and any other solid surfaceby increasing the distance between the two contacting surfaces, therebyminimizing blocking; antimicrobial function (with one or moreantimicrobial agents present); tactile function where the functionalcomposition enhances the tactile experience (or “feel”) of theopacifying layer; antistatic function to reduce static charge; and asoil resistance function to reduce potential soiling. These functionalproperties can be provided by one or more described components (i),(ii), (iii), (iv), and (v) in the functional composition, and somecomponents can provide multiple functions.

Useful (i) glass particles generally have an average particle size of atleast 5 μm, or at least 20 μm and up to and including 100 μm, or up toand including 60 μm, or even at least 20 μm and up to and including 40μm. Average particle size can be determined by using known proceduresand equipment to measure the largest diameter of a plurality of (i)glass particles and determining an arithmetic average.

Useful (i) glass particles can be made from different chemical types ofglasses. This includes soda-lime borosilicate, alkali-free or fusedsilica, among other specialized glasses. Such materials can be obtainedfrom various commercial sources or prepared using known procedures andstarting materials. While solid glass particles can be used in someembodiments, it is desirable that the (i) glass particles are “hollow”glass particles having a single void volume surrounded by a “shell” ofglass. Such hollow glass particles typically do not contain multiplevoids or “pores” within the particle volume. Examples of usefulcommercial materials of this nature include soda-lime-borosilicatehollow glass spheres from 3M that are available as a series of productsfor different applications, for example, the S series, K series, iMseries, XLD series, and HGS series. Of these the iM16K hollow glassparticles are particularly desirable.

The (i) glass particles can have a density of at least 0.1 g/cm³ and upto and including 2.2 g/cm³ depending upon whether they are hollow glassparticles or solid glass particles. For example, useful solid glassparticles can have a density of up to 2.2 g/cm³, while useful hollowglass particles can have a density of at least 0.1 g/cm³ and up to andincluding 0.7 g/cm³.

The (i) glass particles can be present in the functional composition inthe foamed, opacifying element in an amount of at least 10 weight % andup to and including 99 weight %, or more likely of at least 25 weight %and up to and including 80 weight %, based on the total weight of thefunctional composition. The corresponding amounts of the (i) glassparticles (for example, hollow glass particles) in the functionalcomposition formulation can be determined as at least 0.25 weight % andup to and including 20 weight %, or at least 0.5 weight % and up to andincluding 10 weight %, all based on the total weight of the functionalcomposition formulation.

In some embodiments, the functional composition formulation contains (i)hollow glass particles having an average particle size of at least 10 μmand up to and including 60 μm, which are present in an amount of atleast 0.25 weight % and up to and including 20 weight %, based on thetotal weight of the functional composition formulation.

Optionally, a (ii) solid or non-solid lubricant can be present in thefunctional composition. Each solid lubricant generally has acrystallinity of at least 50% and melt very little at temperatures below40° C. Its wax melt viscosity can be at least 5 centipoise (5 mPa-sec),or at least 10 centipoise (10 mPa-sec) and up to and including 100centipoise (100 mPa-sec). Mixtures of the same or different types ofmaterials can be used if desired. For example, such solid (ii)lubricants can be selected from one or more components of the groupconsisting of nonliquid waxes, metal esters of fatty acids such ascalcium soaps, graphite, silicone-based polymers, and fluoropolymers, ora combination of any of the same or different types of these materials.The (ii) lubricants are different compositionally from the (i) hollowglass particles described above.

Useful nonliquid waxes include but are not limited to, polyolefins suchas polyethylene wax and polypropylene wax as well as long chainhydrocarbon waxes such paraffin wax. Other useful nonliquid waxesinclude carbonyl group-containing waxes such as long-chain aliphaticester waxes; polyalkanoic acid ester waxes such as montan wax,trimethylolpropane tribehenate, and glycerin tribehenate; polyalkanolester waxes such as tristearyl trimellitate, and distearyl maleate; andpolyalkanoic acid amide waxes such as trimellitic acid tristearyl amide.Examples of useful aliphatic amides and aliphatic acids includeoleamide, eucamide, stearamide, behenamide, ethylene bi)oleamide),ethylene bis (stearamide), ethylene bis(behenamide), and long chainacids include but are not limited to, stearic, lauric, montanic,behenic, oleic, and tall oil acids. U.S. Patent Application Publication2010/0021838 (Putnam et al.) describes some representative nonliquidwaxes in [0054], the disclosure of which is incorporated herein byreference. Useful materials of this type can be obtained from variouscommercial sources.

Useful metal esters of fatty acids include but are not limited to,compounds of metals complexed with fatty acids that are derived fromvegetable oils or animal tallow, such as sodium, potassium, calcium,magnesium and aluminum soaps, wherein the fatty acids comprise at least12 and up to and including 20 carbon atoms and are generally saturatedor mono-unsaturated in nature. Representative compounds of this type,such as calcium stearate, can be obtained from various commercialsources.

Graphite can be provided in various forms and obtained from commercialsources.

A useful fluoropolymer is polytetrafluoroethylene (PTFE or Teflon) butother polymers comprising at least some fluorinated moieties can also beused if they have lubricating properties.

Non-solid lubricants are also useful including but not limited to,silicone-based polymers such as polydimethylsiloxanes having a molecularweight less than 10,000.

A (ii) lubricant described herein can be present in the functionalcomposition at a dry coverage of at least 0.01 g/m² and up to andincluding 30 g/m² or at least 1 g/m² and up to and including 20 g/m².The amount of such materials in the functional composition formulationto supply these “dry” coverages would be readily determined by a skilledworker.

Moreover, (iii) tinting materials can be present in the functionalcomposition and can be one or more pigments, one or more dyes, or anycombination thereof. For example, the (iii) tinting material can be usedto provide a ΔE 2000 value of at least 3.5, and more likely of at least4 relative to the same foamed, opacifying element from which thefunctional composition has been omitted (not applied). By “same,” it ismeant that all components and structures of the two foamed, opacifyingelement are identical as best they can be made so, but one foamed,opacifying element contains a functional composition and the other doesnot.

In some embodiments, one or more white pigments as (iii) tintingmaterials can be present to provide a “whiter” appearance in the foamed,opacifying element, that is providing an L* value greater than 70 (oreven greater than 80). Useful white pigments useful for this purposeinclude but are not limited to titanium dioxide, barium sulfate, calciumcarbonate, and combinations of two or more of such materials.

Other useful (iii) tinting materials can comprise cyan, magenta, yellow,red, green, or blue pigments, or combinations two or more thereof, thatreflect or scatter in a region of the visible electromagnetic spectrumto produce the desired coloration or hue. Moreover, white pigments canbe combined with one or more of the cyan, magenta, yellow, red, green,or blue pigments. Other useful pigments suitable for use as (iii)tinting materials include, but are not limited to, titanium dioxide,titanium coated mica, barium sulfate, calcium carbonate, zinc oxide, azopigments, monoazo pigments, di-azo pigments, azo pigment lakes, Naphtholpigments, Naphthol AS pigments, benzimidazolone pigments, di-azocondensation pigments, metal complex pigments, isoindolinone andisoindoline pigments, polycyclic pigments, phthalocyanine pigments,quinacridone pigments, perylene and perinone pigments, thioindigopigments, anthrapyrimidone pigments, flavanthrone pigments, anthanthronepigments, dioxazine pigments, triarylcarbonium pigments, quinophthalonepigments, and diketopyrrolo pyrrole pigment. Other examples of usefultinting materials are described in [0052] of U.S. Patent ApplicationPublication 2010/0021838 (noted above).

In all embodiments, the (iii) tinting material is not the same materialas the (i) hollow glass particles or the (ii) lubricant. The (iii)tinting material, however, can be the same as or different from thetinting colorants present as (c) additives in the opacifying layer.

Such (iii) tinting material can be present in the functional compositionat a dry coverage of at least 0.01 g/m² and up to and including 45 g/m²or at least 5 g/m² or up to and including 25 g/m². The actual amount oftinting material added depends on the strength or covering power of thechosen colorant(s). The amount of a (iii) tinting material in thefunctional composition formulation would be readily determined by askilled worker to provide these “dry” coverages.

The functional composition can also comprise one or more (iv)water-soluble or water-dispersible organic polymeric binders, each ofwhich generally has T_(g) below 25° C. (determined as described above)in which the (i) hollow glass particles and other components aredispersed. The (iv) water-soluble or water-dispersible organic polymericbinder can be film-forming, that is, it can form a film once applied anddried. Such materials can be self-crosslinkable or crosslinkable using asuitable (v) crosslinking agent as described below. Useful (iv)water-soluble or water-dispersible organic polymeric binders include butare not limited to, film forming polymers such as a partially hydrolyzedpolyvinyl acetate, poly(vinyl alcohol), poly(vinyl pyrrolidone),cellulosic polymers (such as carboxymethyl cellulose and hydroxymethylcellulose), a polysaccharide, a poly(ethylene oxide), acrylamidepolymers, polyester ionomers, gelatin or gelatin derivatives, gellan,starches, polyethylene imine, polyvinyl amine, and derivatives of thesematerials, fluorinated polymers such as fluorinated polyurethanes,polymers containing siloxane moieties, polyurethanes, urethane-acryliccopolymers, other acrylic polymers derived at least in part from one ormore acrylic esters or methacrylic esters, styrene-acrylic copolymers,vinyl polymers, polyesters, or a combination of two or more of same ordifferent types of these organic polymer binders. Such (iv) organicpolymeric binders are readily available from various commercial sourcesor prepared using known starting materials and synthetic conditions. Forexample, a useful fluorinated polyurethane is available as 3M® StainResistant Additive SRC-220 from 3M Company. Yet another useful materialis a self-crosslinking copolymer derived from n-butyl acrylate, ethylacrylate, and N-methylol acrylamide having a glass transitiontemperature (T_(g)) that is less than −5° C. The (iv) water-soluble orwater-dispersible organic polymeric binder can be useful in thefunctional composition for adhering the (i) hollow glass particles andother noted components to the outer surface of the dry opacifying layerand, to provide an enhanced level of abrasion resistance andcohesiveness.

The (iv) water-soluble or water-dispersible organic polymeric binder canbe present in the functional composition in an amount of at least 1weight % and up to and including 90 weight %, or typically at least 5weight % and up to and including 75 weight %, based on the totalfunctional composition weight. Such materials can be present in thefunctional composition formulation in an amount of at least 0.05 weight% and up to and including 5 weight %, or of at least 0.1 weight % and upto and including 2 weight %, based on the total weight of the functionalcomposition formulation. It is also possible to have a weight ratio of(i) glass particles to the (iv) water-soluble or water-dispersibleorganic polymeric binder of from 10:1 to and including 1:5.

It may be beneficial to chemically crosslink some (iv) water-soluble orwater-dispersible organic polymeric binders that are crosslinkable toimprove functional composition cohesiveness by including a (v)crosslinking agent. Such (iv) water-soluble or water-dispersible organicpolymeric binders can be at least partially curable or crosslinkable andcan be cured up to and including 100% of all potential curable orcrosslinking sites. The identity and amount of a suitable (v)crosslinking agent will depend on the choice of (iv) water-soluble orwater-dispersible organic polymeric binder and its reactivity with the(v) crosslinking agent, the number of crosslinking sites available,compatibility with other functional composition components, andmanufacturing constraints such as functional composition formulation potlife, application means, and drying speed. Non-exclusive examples of (v)crosslinking agents include glyoxal, CARTABOND® TSI (Clariant),CARTABOND® EPI (Clariant), SEQUAREZ® 755 (Omnova), glutaraldehyde sodiumbisulfate complex (Aldrich), Sunrez 700M (Om nova), Sunrez 700C(Omnova), CR-5L (Esprix), bis(vinyl) sulfone, bis(vinyl) sulfone methylether, adipoyl dihydrazide, epichlorohydrin polyamide resins, andurea-formaldehyde resins. In one embodiment, a crosslinked (iv)water-soluble or water-dispersible organic polymeric binder includes ahydrolyzed polyvinyl acetate polymer that has been crosslinked using an(v) epichlorohydrin polyamide resin compound. The amount of suitable (v)crosslinking agent in the functional composition formulation would bereadily apparent to one skilled in the art.

It is also desirable in many embodiments, for the (i) glass particles inthe functional composition to be hollow glass particles. and the weightratio of such hollow (i) glass particles to the (iv) water-soluble orwater-dispersible organic polymeric binder that is present, is at least10:1 to and including 1:5.

The functional composition can be prepared from application of afunctional composition formulation that can also include one or morecoating aids (or wetting surfactants) to aid in the coating ordeposition of the functional composition formulation. If a layer of afunctional composition is desired to cover essentially all of thesubstrate surface using a known coating procedure, any coating aid (orwetting surfactant) that will lower the surface tension of thefunctional composition formulation sufficiently to preventedge-withdrawal, repellencies, and other coating defects can be used.For example, useful coating aids (or wetting surfactants) include butare not limited to, alkyloxy- or alkylphenoxypolyethers and polyglycidolderivatives and their sulfates, such as nonylphenoxypoly(glycidol) thatare available from Olin Matheson Corporation; sodiumoctylphenoxypoly(ethyleneoxide) sulfate; organic sulfates andsulfonates, such as sodium dodecyl sulfate, sodium dodecyl sulfonate,sodium bis(2-ethylhexyl)sulfosuccinate (Aerosol OT); and alkylcarboxylate salts such as sodium decanoate.

If the functional composition formulation is to be disposed on the dryopacifying layer by spraying, coating aids (or wetting surfactants knownin the art as spreading agents that are capable of reducing the surfacetension substantially to aid in the formation of small drops) can bepresent. Examples of such coating aids are trisiloxanes like SILWET®L-77 and L-7608, and acetylenic diols such as SURFYNOL® 104 andSURFYNOL® 104A. Useful coating aids (wetting surfactants) generally havea hydrophilic-lipophilic (HLB) balance number of at least 5, or of atleast 7. HLB is a known parameter used to define the hydrophilic andlipophilic properties and components of surface active agents and can bedetermined using known methods and apparatus.

Useful coating aids can be present in the functional compositionformulation in an amount of at least 0.01 weight % and up to andincluding 5 weight %, based on the total weight of the functionalcomposition formulation.

Useful thickeners that can be present singly or in combinations in thefunctional composition formulation are generally non-associativethickeners, and examples of which are alginin, guar gum, locust beangum, xanthan gum, acrylic polymers that are alkali swellable, agar,carboxymethyl cellulose, pectin, and carrageenan. Such thickeners can bepresent in the functional composition formulation in an amount of atleast 0.001 weight % and up to and including 10 weight %, based on thetotal weight of the functional composition formulation.

The functional composition can include one or more of other optionaladditives that provide various properties or characteristics. Forexample, the functional composition formulation can include a biocide orantimicrobial agent of which there are numerous materials known in theart for this purpose (including silver metal and silver salts);antistatic agents known in the art to dissipate electrical charge andstatic; tactile modifiers that change the “feel” of outer surface of thefoamed, opacifying element; visual modifiers that provide a matte,opalescent or other such desirable look; and soil resistance agents thatreduce the potential for soiling from handling or spills. Combinationsof the same or different type of material can be present.

For some embodiments, the functional composition formulation is anaqueous dispersion (containing water as the predominant solvent)comprising: hollow glass particles as the (i) glass particles; a (ii)lubricant; a (iii) tinting material; a (iv) water-soluble orwater-dispersible organic polymeric binder; a (v) crosslinking agent forthe (iv) water-soluble or water-dispersible organic polymeric binder (ifcrosslinkable); a thickener; and a coating aid having ahydrophilic-lipophilic balance number of at least 5.

Method of Providing Functional Compositions and Foamed, OpacifyingElements

The foamed, opacifying elements according to the present invention areprepared using essential functions A) through F) described below, andgenerally in the listed order.

Firstly, the method is carried out by A) providing a substrate having afirst opposing side (or surface) and a second opposing side (orsurface). Useful substrate materials are described above.

A foamable aqueous composition as described above consisting essentiallyof components (a) through (e) in the described amounts and having atleast 35% solids and up to and including 70% solids, is foamed in asuitable manner to provide a foamed aqueous composition. A foamableaqueous composition can be aerated to provide a foamed aqueouscomposition having a foam density of at least 0.1 g/cm³ and up to andincluding 0.5 g/cm³, or of at least 0.15 g/cm³ and up to and including0.4 g/cm³, or even of at least 0.15 g/cm³ and up to and including 0.27g/cm³. This aeration procedure can be carried out using suitableconditions and equipment that would be readily apparent to one skilledin the art in order to create a “foam”, for example in the presence of afoaming agent that is present as at least one of the (c) one or moreadditives described above. For example, aeration can be carried out bymechanically introducing air or an inert gas (such as nitrogen or argon)in a controlled manner. High shear mechanical aeration can be carriedout using sonication or high-speed mixers, such as those equipped with acowles blade, or with commercially available rotorstator mixers withinterdigitated pins such as an Oakes mixer or a Hobart mixer, byintroducing air under pressure or by drawing atmospheric air into thefoamable aqueous composition with the whipping action of the mixer.Suitable foaming equipment can be used in a manner to provide thedesired foam density with modest experimentation. It can be useful tochill or cool the foamable aqueous composition below ambient temperatureto increase stability by increasing composition viscosity, and toprevent its collapse. This chilling operation can be carried outimmediately before, immediately after, or during the aeration procedure.Stability of the foamed aqueous composition can also be enhanced by thepresence of a foam stabilizing agent as another of the (c) one or moreadditives.

Once the foamed aqueous composition has been formed, it can be B)disposed or applied to the first opposing side of a suitable substrate(described above), such as a porous woven substrate. This procedure canbe carried out in any suitable manner that does not undesirably diminishthe foam density (or foam structure) of the foamed aqueous composition.For example, the substrate first opposing surface can be coated with theaqueous foamed composition using any suitable known coating equipment(floating knife, hopper, blade, or gap) and coating procedures includingbut not limited to, blade coating, gap coating such as “knife-over-roll”and “knife over table” operation, floating knife, slot die coating, orslide hopper coating, especially if multiple layers are applied to thesubstrate in the same operation. Useful layer forming (coating) meansare described, for example, in U.S. Pat. No. 4,677,016 (noted above),the disclosure of which is incorporated herein by reference for suchcoating details.

In many embodiments, the foamed aqueous composition can be disposeddirectly onto the first opposing surface of the substrate (“directly”means there are no intervening or intermediate layers).

The amount of foamed aqueous composition to be applied should besufficient to provide a dry coverage of less than or equal to 10 ounces(mass)/yard (or less than or equal to 339.08 g/m²), or at a dry coverageof at least 1.5 ounces (mass)/yard² (or 50.86 g/m²) and up to andincluding 7 ounces (mass)/yard² (237.35 g/m²).

Once the foamed aqueous composition has been formed on the firstopposing surface of the substrate, it can be C) dried to provide a dryopacifying layer, wherein “dry” is defined in relation to the amount of(d) aqueous medium that is present, as described above for the dryfoamed aqueous composition or dry opacifying layer. There may be somepartial and unintentional curing of the (b) binder material at thispoint to form some (b′) matrix material, but it is generally notdesirable for substantial curing to take place during the C) drying.Drying can be accomplished by any suitable means such as by heating withwarm or hot air, microwaves, or IR irradiation at a temperature and timesufficient for drying (for example, at less than 160° C.) to provide adry opacifying layer.

After drying, the dry opacifying layer on the substrate can be D)densified or crushed on the substrate to reduce the foamed layerthickness. Thus, the C) drying and D) densifying operations can becarried out sequentially without much delay between the two features. Adensified or crushed dry opacifying layer is formed using thiscombination of functions.

D) Densifying or crushing is a process of subjecting the dry opacifyinglayer to mechanical pressure, to densify the foam cells and to reduceoverall layer thickness. This process can be carried out in any suitablemanner, but it is generally carried out by a process that providespressure to the dry opacifying layer, for example, by passing it whileon the substrate through a compression calendering operation, pressingoperation, or embossing operation, or a combination thereof. Forexample, the dry opacifying layer on the substrate can be pressedbetween flat plates or through nip rollers under pressure, or it can bepassed through a combination of calendering and embossing rollers toreduce the thickness of the dry opacifying layer and to densify the foamcells. The original thickness of the dry opacifying layer can be reducedby at least 20% (by volume) during such an operation. This process canbe considered a “densifying operation” as the dry opacifying layer ismade denser while it is pressed together. The thickness of the dryopacifying layer before and after densifying can be determined by aknown technique such as laser profilometry.

The D) densifying process can be carried out at any suitable temperatureincluding room temperature (for example, 20-25° C.) and up to andincluding 90° C., or more likely at a temperature of at least 20° C. andup to and including 80° C. The D) densifying process is carried out atnip pressures that are suitable for the construction of the substrateincluding the openness factor to prevent over crushing and consequentloss of uniform opacity of the dry opacifying layer. A useful crushingpressure can be determined using routine experimentation depending uponseveral factors including the foamed aqueous composition formulation andtype of substrate used. For example, a useful densifying pressure can beat least 15 psi (103.4 kPa) and up to and including 200 psi (1379 kPa).

Once D) densifying is completed, a suitable functional compositionformulation as described above, can be applied in the E) feature in asuitable manner to the dry opacifying layer. For example, the applyingstep E) can be carried out immediately after the D) densifying stepwithout intermediate steps.

At some time after the D) densifying operation, the method according tothis invention comprises E) applying or disposing a functionalcomposition formulation to the dry opacifying layer, which functionalcomposition formulation comprises the (i) glass particles describedabove. In many embodiments, the functional composition formulation isdisposed directly on the dry opacifying layer so there are nointermediate layers of compositions.

The functional composition formulation can be disposed on the dryopacifying layer using any number of suitable application techniquessuch as uniformly or non-uniformly spraying, wrapped wire rod coating,rotary screen coating, air knife coating, screen printing, gravurecoating or flexographic coating (or other offset coating techniques),reversed roll coating, slot coating, gap coating, blade coating,extrusion hopper coating, roll coating, slide coating, curtain coating,pad coating, and other techniques that would be readily apparent to oneskilled in the art. For example, application of the functionalcomposition formulation can be carried out using an engraved flexible ornon-flexible roller in an “anilox coating system” where the functionalcomposition formulation, usually of controlled viscosity, is depositedon the flexible or non-flexible roller. A doctor blade is used to meterexcess fluid from the surface leaving just the measured amount of fluidin the engraved cells. The anilox roll then rotates to contact the outersurface of the dry opacifying layer that receives the functionalcomposition formulation from the cells.

It is also particularly desirable to apply the functional compositionformulation in a non-contact manner onto the dry opacifying layer suchas using any suitable spray apparatus and system, especially when thefunctional composition formulation comprises one or more coating aids(wetting surfactants) described herein. There are several methods forspraying fluids onto surfaces that are known in the art and that can beused in the practice of this invention. These include compressed airspraying that converts the drops of the functional compositionformulation into a mist; electrostatic spray systems where applicationof electric field at the nozzle controls the drop size and the electricfield between the drop of functional composition formulation and thesurface controls its deposition; ultrasonic spray systems where theultrasonic energy can be used to create a mist of uniform drop size ofthe functional composition formulation; and rotary spray that usescentrifugal force to atomize the functional composition formulation. Themost common spray technology uses fluid pressure and nozzle design tocreate functional composition formulation drops of a desired size. Inaddition to controlling drop size, nozzle designs also include thegeometry of an ensemble of drops exiting the nozzle. Such geometriesinclude for example, a cone, a fan (trapezoidal), or a jet. The choiceof the geometry is selected based on the application method, and dependsupon the orientation between the spray nozzle and the substrate andwhether the spray system is mobile and the surface is stationary or viceversa or a combination of the two.

A desirable method of applying the functional composition formulationaccording to the present invention is to use a stationary spray systemwith a moving surface. In this instance, the desired geometry of theensemble of functional composition formulation drops exiting a nozzle isa that of a fan with the article containing the dry opacifying layermoving perpendicular to the plane of the fan. When the surface width islarger than the width of the fan, multiple nozzles can be employed andspaced apart such that the overlapping sprays from adjacent nozzlescreates a uniform coverage of drops across the width of the surface. Inaddition to using hydraulic pressure to disperse the drops, othermechanical forces such as nozzle pulsation, ultrasound, centrifugalforce, or air currents, or a combination of two or three of these means,can be used to aid uniform distribution of the functional compositionformulation onto the surface. Another aspect of controlling theuniformity of depositing the functional composition formulation is tocontrol its properties, specifically its viscosity and surface tension,properties well known to those of ordinary skill in the art. For examplefor achieving desirable small drops, the viscosity and surface tensionat the shear rates experienced at the nozzle should be as low aspossible. Shearing thinning fluids are preferred such that the viscosityat the nozzle shear rates is as low as possible. In such embodiments,the functional composition formulation can also include a suitablecoating aid (wetting surfactant) that can lower the dynamic surfacetension of the functional composition formulation and provide the lowestsurface tension. Useful coating aids (or wetting surfactants) for thispurpose include those based on silicones such as for example,organo-modified trisiloxanes as well as the others described above.

A uniformly distributed coating can be formed over (or directly on) thedry opacifying layer, or discontinuous applications can be made toprovide regular or irregular patterns by spraying or other applicationtechniques. When disposed in a discontinuous manner, the functionalcomposition can be present as isolated discontinuous patterns orcoalesced to form a uniform deposition on to the dry opacifying layer.

The applied functional composition formulation can be dried by simpleevaporation of water and any other solvents, to form the functionalcomposition on the dry opacifying layer. This drying can be acceleratedby known techniques such as convection heating including forced air orinfrared heating, or other means that would be apparent to one skilledin the art. The drying can also be carried out or continued in the F)curing operation described as follows.

F) Curing the applied functional composition formulation and the dryopacifying layer can then be carried out under suitable conditions knownto one skilled in the art, for example to convert most or all of the b)binder materials to form (b′) matrix materials. For example, curing (anddrying) can be accomplished using heat or infrared radiation or otherconditions to which the (b) binder materials and catalysts in the dryopacifying layer, and the (iv) water-soluble or water-dispersibleorganic polymeric binder(s) and (v) crosslinking agents, are responsiveto achieve crosslinking. In some embodiments, a suitable functionalizedself-crosslinking latex composition can be used as the (b) bindermaterial, as the (iv) water-soluble or water-dispersible organicpolymeric binder, or both. During this operation, a curing orcrosslinking reaction can occur between reactive side groups of suitablecurable polymer chains.

The resulting foamed, opacifying element can exhibit a bending stiffness(or “bending force”) as determined using the L&W Stiffness Test(described below) of at least 0.15 milliNewtons meter (mN-m).

Further details of coating and drying techniques are described infurther detail in Research Disclosure No. 308119, December 1989, pages1007-1008 and in references cited therein. Curing of the appliedfunctional composition can also be carried out during or subsequently toF) curing at temperatures for example, from 100-160° C.

The dry opacifying layer can be embossed after the C) drying step andbefore the F) curing step using the procedure and equipment describedbelow.

Alternatively, after the F) curing operation, it is possible to providean embossed design on an outer surface of the foamed, opacifyingelement, for example by patterned embossing or calendering the outersurface, to create selected regions of high or low opacity andthickness. The resulting embossed design can be viewed from either sidein transmission.

It is further possible to form images on either outer surface of thefoamed, opacifying element, with or without a primer, using any suitableprinting means such as inkjet printing, screen printing, or flexographicprinting, thereby forming printed images of text, pictures, symbols, orcombinations thereof. Such printed images can be visible, or they caninvisible to the unaided eye (for example, using fluorescent dyes in theprinted images). Alternatively, the outer surface can be covered bysuitable means with a colorless layer to provide a desired protectivefinish. In many instances, the image formed in this manner, for example,on one outer surface, is not visible or discernible from the other outersurface.

A thermally printed image can be formed on either outer surface, forexample, by using a thermal (sublimable) dye transfer printing process(using heat and with or without pressure) from one or more thermal donorelements comprising a dye donor layer comprising one or more dyesublimation printable colorants. For example, a thermal colorant imagecan be obtained using one or more thermal dye patches (containingappropriate one or more dye sublimation thermal transfer colorants) withor without a thermal colorless (clear) patch. Useful details of such aprocess are provided in U.S. Pat. No. 10,145,061 (Nair et al.), thedisclosure of which is incorporated herein by reference.

Thus, dye sublimation thermal transfer printing is a method to impart adesired color or color pattern or image to an outer surface of asynthetic fabric substrate such as polyester, nylon and acrylicmaterials. Dye sublimation thermal transfer printing utilizes thermallyresponsive inks containing sublimable dyes or colorants that, under theinfluence of heat sublime or vaporize onto the outer surface of thefabric, penetrate the fibers, and become entrained therein or attachedto the textile fiber. Dye sublimation thermal transfer printingprocesses and materials used therein are known and are described innumerous publications, for example, in U.S. Pat. No. 3,363,557 (Blake),U.S. Pat. No. 3,952,131 (Sideman), U.S. Pat. No. 4,139,343 (Steiner),U.S. Pat. No. 6,036,808 (Shaw-Klein et al.), U.S. Pat. No. 8,628,185(Hale et al.), U.S. Pat. No. 9,315,682 (Delys et al.), U.S. Pat. No.4,117,699 (Renaut), U.S. Pat. No. 4,097,230 (Sandhu), U.S. Pat. No.4,576,610 (Donenfeld), U.S. Pat. No. 5,668,081 (Simpson et al.), andU.S. Pat. No. 7,153,626 (Foster et al.), the disclosures of all of whichare incorporated herein by reference.

The following Examples are provided to illustrate the practice of thisinvention and are not meant to be limiting in any manner. The followingmaterials were used in the Examples.

Materials Used in the Following Examples:

The continuous polymeric phase polymers used in the following exampleswere the EASTMAN™ Cellulose Acetate Butyrate 381-0.5 (CAB), a celluloseester, T_(g) of 130° C. (obtained from Chem Point).

COATOSIL™ 77 is nonionic organo-modified trisiloxane surfactant (coatingaid) that was obtained from Momentive Performance Materials.

NALCO® 1060 containing colloidal silica was obtained from Nalco ChemicalCompany as a 50 weight % aqueous dispersion.

The poly(methylamino ethanol adipate) (AMAE co-stabilizer) was preparedusing known procedures and starting materials.

Carboxy methylcellulose (CMC, 250,000 kDa) was obtained from AshlandAqualon as AQUALON™ 9 M31F.

The amphiphilic block copolymer of polyethylene oxide andpolycaprolactone (PEO-b-PCL) 5K-20K, was prepared using the proceduredescribed in U.S. Pat. No. 5,429,826 (Nair et al., the disclosure ofwhich is incorporated herein by reference) where the first number is themolecular weight of the hydrophilic block segment, PEO, and the secondnumber is the molecular weight of the oleophilic block segment, PCL.

TERGITOL® 15-S-7, a C12-C14 secondary alcohol surfactant having an HLBvalue of 12.4, was obtained from the Dow Chemical Corporation.

The optical brightener TINOPAL® OB CO was obtained from BASFCorporation.

Styrene-co-divinyl benzene copolymer (“SD matte”), 6 μm matte beads,were made in-house using known suitable ethylenically unsaturatedpolymerizable monomers and a known polymerization procedure.

The carbon black (K) was used as an (e) opacifying colorant in the formof an aqueous dispersion available as Black Pearls 880 obtained fromCabot Corporation.

DISPERSBYK® 022, a silicone based defoamer, was obtained from BYK-ChemieUSA.

SOLSPERSE® 43000, a polyacrylate polymeric dispersant, was obtained fromLubrizol Corp.

Xanthan gum was obtained under the tradename Kelzan (manufactured byKelco Inc.).

Hollow glass particles were obtained from 3M Corporation under thetradename iM16K. They had an average particle size of 20 μm and adensity of 0.46.

A clay powder was obtained from the THIELE KAOLIN COMPANY® under thetradename SKT-13 and had an average particle size of 0.6 μm.

Polyamide particles were obtained from Arkema, Inc. as ORGASOL® 2001 EXDNat 1, an average particle size of 10 μm and a melting point of 177° C.

Polyamide particles were obtained from Arkema Inc. as ORGASOL® 1002 es5Nat 1 that have an average particle of size of 50 μm and a melting pointof 213° C.

The porous fabric substrates used in the Examples below were composed ofa polyester, having a weight of about 80-110 g/m².

The foamable aqueous composition (CF drapery compound) was made from aformulation comprising a self-crosslinking copolymer (P1) derived fromn-butyl acrylate, ethyl acrylate, and N-methylol acrylamide using aknown procedure, and having a glass transition temperature (T_(g)) ofapproximately −25° C. as the (b) binder material from which the (b′)matrix material was derived, (c) additives titanium dioxide, clayfiller, a flame retardant, and foaming surfactant and foam stabilizingagent. This copolymer P1 was also used as the (iv) water-soluble orwater-dispersible organic polymeric binder in the functional compositionformulations.

Preparation of Pigment Dispersions for Porous Particles:

The opacifying pigment dispersion was prepared by combining dry pigment,a dispersant as described in TABLE I below, and an aqueous medium in asuitable milling vessel. The particle size the pigment was reduced bymilling it using ceramic media until all pigment particles were reducedbelow a diameter of 1 μm as determined by optical microscopy.

TABLE I Colorant Dispersions Dispersant (weight % of Pigment DispersionPigment Pigment) Weight % D-K K SOLSPERSE ® 25 (“black”) 43000 (5)DISPERSBYK ® 022 (0.05)

Preparation of (a) Porous Particles PP:

The (a) porous particles PP used for preparing a foamed, opacifyingelement contained 1 weight % of optical brightener (identified below) inthe continuous CAB polymeric phase and 0.8 weight % opacifying colorant(K) in the discrete pores.

An aqueous phase was made up by dissolving 5 grams of CMC in 240.5 gramsof distilled water and adding to it 4.3 grams of the D-K dispersioncontaining 18.6 weight % of carbon black. This aqueous phase wasdispersed in 831.8 grams of an oil phase containing 97.7 grams of CAB, 2grams of PEO-b-PCL, and 1 gram of the optical brightener, TINOPAL® OB COin ethyl acetate, using a homogenizer. A 975-gram aliquot of theresulting water-in-oil emulsion was dispersed using the Silverson L4Rhomogenizer for two minutes at 1200 RPM, in 1625 grams of a 200 mmolarpH 4 acetate buffer containing 39 grams of NALCO® 1060 colloidal silica,and 9.75 grams of AMAE co-stabilizer followed by homogenization in anorifice homogenizer at 1000 psi (70.4 kgf/cm²) to form awater-in-oil-in-water double emulsion. The ethyl acetate was removedunder reduced pressure at 40° C. after dilution of thewater-in-oil-in-water emulsion with an equal weight of water. Theresulting suspension of solidified porous particles PP was filtered, andthe isolated porous particles PP were washed with water several times,followed by rinsing with a 0.05 weight % solution of TERGITOL® 15-S-7surfactant. The isolated porous particles PP were then air dried. Theyhad a mode particle size of 5.4 μm and a porosity of 46 volume %.Typically, the discrete pores contained within the porous particles PPprepared according to this procedure had an average diameter of from 150nm and up to and including 1,500 nm. The moisture content of the finalpowder was 56%.

Preparation of Foamable Aqueous Compositions; Foamed AqueousCompositions; and Foamed, Opacifying Element A1:

A foamable aqueous composition containing porous particles PP wasprepared by combining 191 grams of porous particles PP with 1209 gramsof CF drapery compound. Porous particles PP were dispersed into themixture by stirring at 1200 rev/minute using a 50-mm diameter Cowlesblade at ambient temperature for 30-60 minutes. The resulting foamableaqueous composition was used to prepare a foamed aqueous compositionunder pressure using an Oakes 2M Laboratory Mixer Model 2MBT1A. Eachresulting foamed aqueous composition, having a foam density of from 0.18g/cm³ to 0.25 g/cm³, was coated onto a (“first opposing”) surface of theporous substrate described above using a coating knife, dried at atemperature of from 85° C. to 145° C. until the moisture content wasless than 2 weight %, and crushed (“densified”) on the porous substratebetween hard rollers under pressure. The dried and crushed opacifyingcomposition was further cured at 160° C. for 2 minutes to crosslink the(b) binder material and form the resulting (b′) matrix material. Theresulting foamed, opacifying element A1 was used to create elementsamples using a functional composition according to the presentinvention. This foamed, opacifying element exhibited an optical density(OD) of 5.4 for the dry opacifying layer weight of 168 g/m².

Preparation and Use of Functional Composition Formulations:

Xanthan gum (thickener) was stirred into water until it was hydrated.After about 2 hours, it was stirred again into a homogeneous suspension.The organic polymeric binder P1 (50 weight %) was added to thissuspension. COATOSIL™ 77 coating aid (or wetting surfactant) was thenadded with gentle stirring, followed by addition of the hollow glassparticles. The resulting organic polymeric binder P1 amount level was at1 weight %, the xanthan gum thickener was at 0.5 weight % of thesolution, and the COATOSIL 77 was at 0.2 weight %, all based on thetotal weight in the suspension. The hollow glass particles were added todifferent samples of the suspension at varying levels as described inTABLE II below.

The substrate used for the experiments was a woven polyester fabric of adry weight of 2.8 oz/yd² (7.38 g/m²) and having a foamed opacifyinglayer on a surface at a dry coverage of 5.46 oz/yd² (14.39 g/m²).

An atomizing paint sprayer activated with air at 40 psi (2.81 kgf/cm²)was used to spray the functional composition formulations onto the sideof the fabric coated with the opacifying layer. The amount deposited ona fabric substrate was determined by measuring the change in weight of aknown area of the fabric substrate before and after spraying. Sprayedsamples of foamed, opacifying elements were dried in a convection ovenfirst at 135° C. and then at 160° C. to cure and crosslink the materialsin the resulting functional composition.

Release Testing:

A buck press is a clam-shell press that mimics the temperature andpressure in the nip of a thermal dye transfer process (sublimation)printer. It has one side that can be heated and a second side that isnot heated. Both surfaces are padded with a thermally conductive layerand the two surfaces can be pressed together under a controlledpressure. This apparatus was used to thermally print images onto to thesamples of foamed, opacifying elements described above. Each element wassandwiched between a thermal dye donor element and a release paper(obtained from PROTEX, of 19 g/m² weight) with the thermal dye donor incontact with the polyester fabric substrate, and the release paper wasin direct contact with the functional composition of each foamed,opacifying element. The combination (packet) comprising the thermal dyedonor, foamed, opacifying element, and the release paper was placedwithin the buck press where the heated side of the buck press was incontact with thermal dye donor and the un-heated side was in contactwith the release paper. A pressure of 2 psi (0.141 kgf/cm²) andtemperature of 204° C. were maintained for 32 seconds for eachexperiment. After this thermal dye transfer process was carried out, therelease paper was peeled off the functional composition. The ease ofpeeling was rated from 1 through 5 where the 1 is the value for theeasiest release and 5 was the value where the release paper wascompleted stuck to the back side of the polyester fabric substrate.

The following TABLE II shows the various functional compositions used inthe experiments and the release testing and appearance evaluations.

TABLE II Wt. % Release release Release Additive Dry additive Rating of 1Release Weight Laydown in (best) to 5 Appearance of Additive % (g/m²)topcoat (worst) Release Testing Comments spray coating Control: no 5Release paper stuck to opacifying layer functional composition presentClay SK-T 13 15 6.394 90% 3 Release paper needed to be peeled off; didHazy white; not not fall off very uniform ORGANSOL ® 6 4.359 78% 4 Somesticking of release paper but easier to Hazy white; not 2001 EXD removethan for the Control very uniform NAT 1 3M Glass 3 1.918 64% 1 Nosticking of release paper; slid off Uniform Bubbles iM16K 3M Glass 53.526 75% 1 No sticking of release paper; slid off Uniform Bubbles iM16K3M Glass 7 3.925 80% 1 No sticking of release paper; slid off UniformBubbles iM16K None 0 0.620 0% 3 Stuck to release paper but it was easierto Uniform peel than for the Control 3M Glass 0.5 1.066 23% 2 NoSticking of release paper Uniform Bubbles iM16K 3M Glass 1 1.235 37% 1.5No Sticking of release paper Uniform Bubbles iM16K SD matte 5 3.623 75%1.5 Very slight sticking of release paper Some mottle ORGANSOL ® 2 1.92254% 1.5 Very slight sticking of release paper Some mottle 1002 E55 NAT 1ORGASOL ® 5 4.431 75% 1 No sticking of release paper Some mottling 1002ES5 NAT 1 ORGASOL ® 7 5.521 80% 1 No sticking of release paper Whitishcolor with 1002 E55 mottle and non-uniformity NAT 1

The data in TABLE II provide information about the advantages of thepresent invention. The foamed, opacifying elements having a functionalcomposition containing the hollow glass particles exhibited easy releasefrom the release paper. However, those elements in which the functionalcomposition did not contain hollow glass particles exhibited difficultrelease from the release paper.

Moreover, the appearance of the functional compositions used in thepresent invention were very uniform in appearance and differed verylittle in appearance from the foamed, opacifying elements from which afunctional composition had been omitted.

The presence of clay particles in a functional composition required arelatively high amount because of its particle size, and it wasrelatively effective but not as effective as the hollow glass particlesbeads even at a coverage of 10 times higher. More importantly, theappearance of the functional composition containing clay particles washazy and non-uniform, which makes such compositions difficultmanufacture predictably.

The lower melting point of the nylon particles made them ineffective asa release agent in the functional composition, because they did notsurvive the heat of the buck press. As a result, there was some stickingof the release paper to the element. The higher melting point nylonparticles did provide good release properties, but the appearance of thefunctional composition was white and nonuniform.

The SD matte particles were not effective as release agents in thefunctional composition and caused a mottled appearance.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be obtained within the spirit and scopeof the invention.

1. A method for preparing a foamed, opacifying element, the methodcomprising the steps of: A) providing a substrate having a firstopposing side and a second opposing side, B) applying a foamed aqueouscomposition onto the first opposing side of the substrate, C) drying theapplied foamed aqueous composition, to provide a dry opacifying layer;D) densifying the dry opacifying layer to reduce its thickness by atleast 20% compared to its original thickness; E) applying a functionalcomposition formulation comprising (i) glass particles, to the dryopacifying layer, and F) curing the applied functional compositionformulation and the dry opacifying layer to provide a functionalcomposition on the dry opacifying layer, thereby providing a foamed,opacifying element, wherein: the dry opacifying layer comprises: (a) atleast 0.1 weight % and up to and including 35 weight % of porousparticles, each porous particle comprising a continuous polymeric phaseand discrete pores dispersed within the continuous polymeric phase, theporous particles having a mode particle size of at least 2 μm and up toand including 50 μm; (b′) at least 10 weight % and up to and including80 weight % of a matrix material that is derived from a (b) bindermaterial having a glass transition temperature (T_(g)) of less than 25°C.; (c) at least 0.0001 weight % and up to and including 50 weight % ofone or more additives selected from the group consisting of dispersants,foaming agents, foam stabilizing agents, plasticizers, flame retardants,optical brighteners, thickeners, biocides, tinting colorants, metalparticles, and inert inorganic or organic fillers; (d) less than 5weight % of water; and (e) at least 0.002 weight % of an opacifyingcolorant different from all of the one or more additives of (c), whichopacifying colorant absorbs electromagnetic radiation having awavelength of at least 380 nm and up to and including 800 nm, allamounts being based on the total weight of the dry opacifying layer. 2.The method of claim 1, wherein the (i) glass particles have an averageparticle size of at least 5 μm and up to and including 100 μm and arepresent in an amount of at least 10 weight % and up to and including 99weight %, based on the total weight of the functional composition. 3.The method of claim 1, wherein the (i) glass particles have an averageparticle size of at least 20 μm and up to and including 60 μm and arepresent in an amount of at least 25 weight % and up to and including 80weight %, based on the total weight of the functional composition. 4.The method of claim 1, wherein the functional composition is present ata dry coverage of at least 0.5 g/m² and up to and including 15 g/m². 5.The method of claim 1, wherein the (i) glass particles are hollow glassparticles having a density at least 0.1 g/cc and up to and including 0.7g/cc.
 6. The method of claim 1, wherein the (i) glass particles arehollow glass particles having a single void volume surrounded by a shellof glass.
 7. The method of claim 1, wherein the functional compositionformulation further comprises one or both of a (ii) lubricant and a(iii) tinting material.
 8. The method of claim 1, wherein the functionalcomposition formulation further comprises a (iv) water-soluble orwater-dispersible organic polymeric binder that is a poly(vinylalcohol), a partially hydrolyzed polyvinyl acetate, a cellulosicpolymer, a poly(ethylene oxide), a poly(vinyl pyrrolidone), afluorinated polymer, a polymer containing siloxane moieties, an acrylicpolymer, an acrylamide polymer, gelatin or a gelatin derivative, gellan,a polysaccharide, a polyurethane, a polyester ionomer, or a combinationof two or more of these materials.
 9. The method of claim 8, wherein thefunctional composition formulation further comprises a (v) crosslinkingagent for the (iv) water-soluble or water-dispersible organic polymericbinder that is crosslinkable.
 10. The method of claim 8, wherein the (i)glass particles are hollow glass particles and the weight ratio of thehollow glass particles to the (iv) water-soluble or water-dispersibleorganic polymeric binder is at least 10:1 to and including 1:5.
 11. Themethod of claim 1, wherein the applying step E) is carried out after theD) densifying step without intermediate steps.
 12. The method of claim1, wherein the dry opacifying layer is embossed after the C) drying stepand before the F) curing step.
 13. The method of claim 1, wherein theapplying step E) is carried out by spraying the functional compositionformulation that further comprises a coating aid, and the spraying iscarried out using hydraulic pressure in a spray system to disperse dropsof the functional composition formulation, aided by nozzle pulsation.14. The method of claim 1, wherein the dry opacifying layer comprises atleast 0.5 weight % and up to and including 25 weight % of the (a) porousparticles that have a mode particle size of at least 3 μm and up to andincluding 20 μm, the amount based on the total weight of the dryopacifying layer.
 15. The method of claim 1, wherein a carbon black ispresent as the (e) opacifying colorant in the dry opacifying layer in anamount of at least 0.002 weight % and up to and including 1 weight %,based on the total weight of the dry opacifying layer.
 16. The method ofclaim 1, further comprising forming an image on an outer surface of thefoamed, opacifying element.
 17. The method of claim 16, comprisingforming the image by printing one or more dye sublimation thermaltransfer colorants on the outer surface.
 18. The method of claim 1,comprising applying the functional composition formulation in E)directly on the dry opacifying layer.
 19. The method of claim 1, whereinthe functional composition formulation is an aqueous dispersioncomprising: hollow glass particles as the (i) glass particles; a (ii)lubricant; a (iii) tinting material; a (iv) water-soluble orwater-dispersible organic polymeric binder; a (v) crosslinking agent forthe (iv) water-soluble or water-dispersible organic polymeric binder ifit is crosslinkable; a thickener; and a coating aid having ahydrophilic-lipophilic balance number of at least
 5. 20. The method ofclaim 1, comprising providing an embossed design on an outer surface ofthe foamed, opacifying element.